Once Per Episode

""Shh.. It's the episode where he learns a life lesson and writes about it in his journal!""

- Real Life Comics, on Doogie Howser, M.D.

""Ohh yeah, right. I remember now, it's like from... every other episode...""

- Kronk reacting to a Running Gag in The Emperors New School

A relative of the Running Gag. This is an event that, instead of happening several times in one episode, happens one time in just about every episode of a show.

There is an entire genre of jokes that exists to take advantage of this trope: "Remember that one episode of _____ where...". For example: Remember that one episode of Gilligan's Island where they almost escape from the island, but Gilligan screws it up?

Compare Signature Style. If it happens at the end of an episode, it's Every Episode Ending. If everything is like this, it is Strictly Formula.

Also compare Once a Season, where a certain plotline or character story gets a yearly invite. May also overlap with Different in Every Episode if the series follows a specific formula for its references and plots.

Anime and Manga
"Ranma: Stupid one-topless-scene-per-episode contract!"
 * Kanon: Ayu runs into Yuuichi, literally or not, in every episode except for the ends of the other girls' arcs.
 * Trigun features a cat skittering across the screen every episode, some times more obviously than others.
 * Tokyo Mew Mew: Magical Girls have to transform once an episode, but in Tokyo Mew Mew, it got bad enough to be an in-joke with fans—hey, there aren't even monsters around! What's Mew Ichigo doing exactly?
 * Nishizawa of Hayate the Combat Butler eats something while (after her introduction in episode 12) thinking wistfully of Hayate. (She still appears doing it even before her official introduction.)
 * Serial Experiments Lain: The opening Aspect Montage. Showing Lain on the street outside her house where the shadows aren't quite right.
 * Clannad: After Fuko's arc of concludes, she makes random appearances in accordance with this trope.
 * There's a Running Gag in .hack//Legend of the Twilight about Shugo getting bashed in the face and losing a tooth every episode. Fortunately for his dentistry the damage isn't permanent or cumulative, since he is in virtual form when it happens. The gag is dropped in the last few episodes which take a more serious turn.
 * In every episode of most Cutey Honey incarnations (except the recent The Live TV series) someone would ask Honey who she is, to which she would laugh, list her different costumes for the episode (usually three) and finish by "but the truth is... Honey Flash!" (cue transformation sequence) "Cutey Honey! The Warrior of Love!"
 * Every single episode of the Medabots dub found an excuse for Ikki to shout "Metabee!". Also: "Medafighters Ready? Medabots... Robattle!"
 * Kamichama Karin: "Mr. Glasses Man!" "I am not 'Mr. Glasses Man'!"
 * Excel Saga:
 * Someone (usually Pedro) gives a Big No each episode.
 * Nabeshin appears in every episode, even if it's just for a second.
 * Excel getting dropped through a trapdoor by Il Palazzo. One time the rope he pulls to spring the trap has a sign saying "obligatory" hung on it.
 * Mnemosyne has Rin asking Mimi for water every morning, only to get vodka (which is Russian for "water") instead.
 * Not to mention Rin getting mutilated and/or killed, which on average, actually happens closer to thrice an episode.
 * Sayonara, Zetsubou-sensei
 * Itoshiki-sensei says "I'm in despair!" (or "Zetsuboushita!" in Japanese) at least once after a short clip of him looking surprised/afraid/overly-dramatic in different directions. Usually, he'll give the full line: "I'm in despair! X has left me in despair!"
 * Lampshaded several times in the anime when other, usually minor, characters declare "I'm in despair!" and Itoshiki promptly replies along the lines of "Thats MY line."
 * Kaere also gets a panty shot every episode, and there are smaller things like a stork showing up in the background. These are all lampshaded when Itoshiki-sensei tries to explain all the once-per-episode elements to new viewers. He can't come up with a good reason why they're all there.
 * Code Geass R2 has, amazingly, turned the Wham! Episode concept into a Once an Episode occurrence. Seriously, literally, once an episode; R2 is made up of nothing but Wham Episodes.
 * Pokémon:
 * "Looks like Team Rocket's blasting off again!" Averages once an episode. There are episodes where they don't blast off at all (like the first-season episode where Ash got the Thunderbadge, for example), but on the other hand, there are also episodes where they blast off twice, so it all evens out. In addition, Wobbuffet had been seen, or its cry was heard, in every episode since his introduction save two of them.
 * Brock meets a cute girl, immediately proposes to her, and is then dragged off by Misty/Max/Croagunk/whoever. On rare occasions, however, this would turn the other way - the odd episode had Misty gushing over a Water Pokémon (or something related to a water-type) and Brock would drag her away, and one occasion had the cute girl of the week proposing to Brock, leaving him completely dumbfounded.
 * Both are now gone as of Best Wishes, as Brock was finally Put on a Bus, and Team Rocket Took a Level in Badass and now only blast off of their own will....on jetpacks.
 * In Zatch Bell, before Ponygon was introduced as a character, he would often be shown walking across the screen for no explicable reason once an episode.
 * On The Noozles, Osgood the lizard pops up out of nowhere at least once an episode to comment on what is going on.
 * Once per Story Arc variation in Magical Girl Lyrical Nanoha: The major battle near the end of an incident will be capped off with Starlight Breaker. As Sound Stage X showed when  did it, this rule is followed even if Nanoha is absent.
 * In Maicchingu Machiko Sensei, Machiko's panties are shown without fail throughout all 95 episodes, not to mention that she will be disrobed at least partially.
 * Ranma ½: The Abridged Chronicles has several once-per-episode gags, as stated by the creators. This list includes a scene with Genma as a panda with flashing yellow text exclaiming something about the panda, a boot to the head, a musical interlude (usually to draw out fight scenes), someone exclaiming "Son of a bitch," and of course, Ranma getting turned into a girl, usually without a top on. While not all of these happen each episode, they occur enough to qualify.


 * In the original Ranma ½, Ranma's transformation initially is this, but is increasingly Averted or implied to happen offscreen. At the very beginning, the threat of it being revealed was once an episode. They didn't so much waste a perfectly good plot, more one of their best gags, not to mention plenty of perfectly good Fan Service opportunities.
 * Let us not forget Rizelmine with the main male character making her cry her explosive tears, although that was backed off a bit in the second season when things got a little more serious. But the dog was still there in every episode.
 * One Piece (the manga) always contains an appearance by Pandaman in almost every arc (or, in one place Pandawoman); sometimes it's obvious but most of the time it's not.
 * Sailor Moon: Usagi's transforms into Sailor Moon is in almost every episode, and in almost all of the other episodes she is already transformed when the episode starts. I think there might have been one where she didn't transform, but I'm not sure. Also, Sailor Moon defeats the Monster of the Week with whatever that season's attack is, if it's not a final battle that involves some more serious moon juju or one of the rare episodes where one of the other Senshi defeats the monster without her.
 * Revolutionary Girl Utena: The pre-duel sequences. Sure, duelling for the Rose Bride is the point of the show, but to recycle a lengthy animation sequence and some remix of "Zettai Unmei Mokushiroku" every single time? Yes, she has to climb stairs to the duel arena (except in the last 13 episodes, when she takes a "gondola"/elevator). We get it already. Stock footage is used quite a lot in the show, partly because of the low budget and partly for emphasis.
 * Additionally, the Shadowplay Girls show up in nearly every episode and comment on every duel.
 * Natsu no Arashi: At least Once Per Episode, sometimes more, there's an anonymous chap in the back calmly asking for salt. A few episodes he comes close, to salt and happiness, only to have it whisked away not unlike Charlie Brown's football.
 * In the first half of Final Fantasy Unlimited, Kaze pulls out his Magun summon weapon, and saves the day. In the second half of the series, he pulls out the Magun and it malfunctions.
 * In every episode of Nerima Daikon Brothers, someone in the band needs to take out a loan, and the band goes to the Rental Shop to get a Plot Coupon from the director.
 * Pinoko in Black Jack presses her cheeks together and yelling, "Acchonburike" (which has no actual meaning except for being translated it as "Ohmigewdness") once per episode whenever something surprising happens.
 * In Black Jack 21, a game was made to try to find the image of Sharaku in each episode. Some being more obvious than others.
 * In the Hidamari Sketch anime, someone, usually Yuno, soaks in bath salts... even if she and the others have already been to a sentō that day. This may or may not end the episode, but it's always at least close. It took a few episodes to get it to its most common form (underwater shot of salts; colored water swishing down the floor drain; the bather in the tub), but the main aspect is pretty much once an episode.
 * In Star Driver, various members of the Glittering Crux Brigade yell "Open the cybercasket!" once an episode in order to summon their Cybodies. Also, there's a Transformation Sequence each episode when Takuto becomes the Galactic Pretty Boy.
 * In each episode of Black Butler, Ciel says, "This is an order!"
 * Additionally, Sebastian will say, "A Phantomhive butler who can't [insert X task - usually an improbable one - here] isn't worth his salt."
 * In the series Infinite Ryvius, one will spot Kibure Kikki, a strange female student in a dinosaur costume at the first episode. Each episode after that one can usually find her in a blink and you miss it scene of her trying to find the parts of said costume throughout the ship. Many fans have even made into a Where's Waldo type game to try to find her in each ep.
 * THE iDOLM@STER - The shot of the front of the 765Pro Office.
 * Tsukimiya from Bloody Cross gets groped in almost every chapter.

Comic Books

 * During Mark Waid's run on The Flash, every issue started with the lines "I'm Wally West--the fastest man alive," or some variation thereof. On rare occasion, especially when Wally or a member of his family needs to deliver a speech with emotional punch, other writers still riff on this.
 * Every issue of Spider-Girl opens with "Your name is May "Mayday" Parker, and you are the daughter of Spider-Man," or some variation of it.

Film

 * Star Wars has many, due to the formulaic nature of the films.
 * Every film has the phrase, "I've got a bad feeling about this." Much Expanded Universe material homages this practice.
 * Every movie includes the Wilhelm Scream, a stock sound effect famous enough to have its own trope page. But then, pretty much every action movie features the Wilhelm Scream—a lot of them as a shout out to Star Wars.
 * Every single film contains a Big No, some bigger than others.
 * All films begin with the opening narration scrolling against a starry sky. When the narration ends, the camera pans to a ship flying through space.
 * Every film introduces a new Force power.
 * A New Hope: Jedi Mind Trick / Force Choke
 * The Empire Strikes Back: Telekinesis / Force Jump
 * Return of the Jedi: Force Lightning
 * The Phantom Menace: Force Speed
 * Attack of the Clones: Force Avalanche / Force Absorb
 * Revenge of the Sith: Force Reflect (when Yoda turns Palpatine's lightning back on him)
 * All films have an ending sequence with music and no dialogue.
 * And finally, count on at least one lightsaber battle between Force-users to go down, usually towards the end.
 * Most James Bond films have him say "Bond. James Bond." Which is a problem if you are playing the drinking game. He also gets involved with two or three women per movie, at least one of whom gets killed off. (see also the series' entry on Strictly Formula)
 * Pirates of the Caribbean had variations of "Why is the rum gone?"
 * 11 of the 12 Marx Brothers films had Chico play the piano and Harpo play the harp.
 * The Swedish comedy movies Jönssonligan always had Sickan say "Jag har en plan" ("I've got a plan").
 * The Danish comedy movies Olsen-Banden, of which Jönsonsligan is a Swedish remake, had Egon Olsen in jail at the beginning of a story, and he'd come out of jail with a plan wrapped in brown paper, and he'd say "Jeg har en plan". And the wonderfully brilliant plan would somehow misfire and Egon would be arrested, usually in the place of the real crook.
 * All Terminator films have someone shouting "Get Out!" as they take over a vehicle. Two other phrases almost qualify: "I'll be back!" (all but T3, which instead features "She'll be back" and "I'm back!"), and "Come with Me If You Want to Live" (T3 features "Do you wanna live?! Come on!!").
 * The first two Back to The Future movies have Marty being unconscious and after waking up says, "You're...You're my mother!" In the third movie, however, he wakes up and says, "You're...who are you?" as it was not his mother this time. The first two movies also had Biff being covered in manure (not the same instance) while the third movie has his ancestor be covered in manure.
 * All three movie feature a wide overhead shot of Marty walking into the town square, looking astonished as he sees his hometown in a different time period, along with a clear shot of the town clock's current state in that particular era.
 * The Tannen family really hates manure.
 * Every Indiana Jones film will include Indy fighting a big strong henchman (in the first three, played by the same actor) who'll end up being killed in an extraordinarily violent fashion.
 * On the other hand, the Big Bad himself is always killed by his own greed or hubris while Indy watches.
 * American Pie: The three main movies feature Stifler coming into unwanted contact with one kind of human excreta or other, Jim getting caught masturbating in a ridiculous way, and Finch having sex with Stifler's Mom. Averted in the fourth movie, American Reunion somewhat, while Jim still gets caught masturbating, Stifler makes someone else come into unwanted contact with his feces, and he has sex with Finch's mom.
 * Almost every official Marvel Comics movie has a Creator Cameo by Stan Lee.
 * X-Men: Hot dog vendor on the beach when the now-mutated senator escapes Magneto.
 * X-Men: The Last Stand: Man watering his lawn in Jean Gray flashback. Bonus points for including Chris Claremont in the same scene, as Stan's neighbor.
 * Spider-Man: Old man shielding little girl from falling debris during the goblin's parade attack.
 * Spider-Man 2: Old man pulling woman away from debris during the battle on the clock tower.
 * Spider-Man 3: Talks to Peter while both are reading a news bulletin about Spider-Man.
 * Hulk: Security guard, bonus points for being alongside Lou Ferigno.
 * The Incredible Hulk: Accidentally drinks soda laced with Banner blood.
 * Fantastic Four: Mailman Willie Lumpkin (the first time he played one of his own characters).
 * Fantastic Four Rise of the Silver Surfer: Denied access to the wedding, despite claiming to being Stan Lee.
 * Iron Man: Mistaken for Hugh Hefner at the casino.
 * Iron Man 2: Mistaken for Larry King at Stark Expo.
 * Daredevil: Old man almost hit by bus.
 * Thor: Truck driver who unsuccessfully tries to tow Thor's hammer from a crater
 * Captain America: The First Avenger: General at the award ceremony.
 * The Avengers: Interviewed about the heroes in the ending.
 * Every Marvel movie featuring the Hulk has him say only two words. In Hulk he says, "Puny human". In The Incredible Hulk he says, "Hulk smash". Finally, in The Avengers he says
 * The Transformers films capping off with a Linkin Park song.

Live Action TV
"Spirit of Jazz: Yorkshire? What is Yorkshire? (or...) Mutant: Freedom? What is freedom?"
 * Someone will call Ed 'The Bowling Alley Lawyer'.
 * Lampshaded by Dean in Supernatural when something strange happens. "Must be Thursday."
 * Remember that episode of Supernatural where one of the brothers is literally on the point of death (or is, indeed, dead) and the other saves him?
 * What about the episode where there is a hot girl who is somehow connected to the Monster of the Week. Okay okay, started fizzling out in the third season, and almost never happened in the finale's or other "complex" episode, but basically every "stand alone" episode in season one or two had one, and it didn't completely fizzle out after season three.
 * On The A-Team the construction montage (in which the team builds a makeshift vehicle/weapon out of stuff they find lying around) would qualify.
 * Or a car flipping over.
 * Mr. T: "I pity the fool".
 * Similarly, Hannibal: "I love it when a plan comes together" + obligatory cigar.
 * Game shows:
 * Family Feud: During the Steve Harvey era, utterance of a part of the male and/or female anatomy or a bodily function. Invariably, a question will be written to elict such a response, with most of the "humor" coming from Harvey's reaction and claiming that it won't be long before the show is canceled for its off-color humor.
 * Match Game: The show that set the standard for double-entendre and utterance of anatomical parts, most commonly "boobs" (or other euphamisms for the word "breast").
 * Klinger's attempts to get a section 8 on M*A*S*H (television). Despite this being a warzone, Klinger had a new dress/frilly female outfit every week. Jamie Farr once recalled the bizarre feeling it gave him walking into the wardrobe department. All of the costumes were on racks assigned to specific actors. Walk past Mike Farrell's rack, there's an army uniform. Walk past Alan Alda's rack, there's a uniform, bathrobe, and maybe a Hawaiian shirt. Get to Jamie's rack(s) and there are just endless frocks, dresses, skirts and bonnets. He maintained the tartan plaid skirt was the most comfortable of them all.
 * A failed escape attempt in Gilligan's Island.
 * The uncle jokes from Welcome Back, Kotter.
 * The avalanche of ping-pong balls on Captain Kangaroo.
 * The message self-destructing after being played at the start of every mission on Mission: Impossible.
 * Except on occasions when Jim is instructed to dispose of it himself "in the usual manner".
 * The inevitable sliming of—and dumping water on—at least one cast member of You Can't Do That on Television, as well as the Opposites series of sketches and the Barth's Diner's Catch Phrase "What (or Who) do you think's in the burger?", followed by Barth's traditional reply "I heard that!" (The vomiting that the question derived was only once every other episode, usually.)
 * The Mighty Boosh
 * A character mistakes Vince for a woman.
 * In the first series, each episode featured at least one character that had part of their costume shaped like a polo mint.
 * The subject of conversation turns to Vince's hair at least once an episode, and in every episode Howard utters the line "... I'm Howard Moon."
 * Rich Fulcher's characters often hit on Vince, and/or proclaim, "A little to the left!" While dying horribly.
 * Bollo frequently "Has a bad feeling about this."
 * Various characters often ask Vince or Howard, "_____? What is _____?"

"House: I finally have a case of Lupus!"
 * Neatly riffed on in Friends, where they are watching Threes Company and Chandler remarks dryly that "this is that episode of Threes Company where there's some kind of misunderstanding". Phoebe frowns, "Then I've already seen this one" and switches the TV off.
 * A similar conversation occurred on Gilmore Girls, where Rory had to tear Jess away from an episode of I Dream of Jeannie. She assured him that "Jeannie is going to get Major Healey out of whatever scrape he's in."
 * The audience expected every Knight Rider episode to have a scene where the car would jump after Michael Knight used the Turbo Boost. Regrettably, and to the disappointment of many a child, not every episode actually featured this (probably due to shortages of Pontiac Firebird bodies to trash...), but the great majority did. Some episodes even featured more than one turbo boost (presumably when they had a few spares available).
 * This was parodied in the Robot Chicken episode that featured them and several other unlikely characters racing where he pressed the turbo and KITT responded, "I can only use the turbo once per episode". It's not true, but that'd ruin the joke.
 * The final season utilized "Super Pursuit Mode" at least Once an Episode. (Though it was three times in the season premiere, just to drive the point home) This was also useful as a time-eating Transformation Sequence.
 * Every episode of Homicide: Life on the Street involves the detectives lying to a suspect or witness to get them to confess/roll over on an accomplice/provide some pertinent information. This tactic is almost uniformly successful, leading to several characters to comment over the course of the series that "crime makes you stupid."
 * Highlander the Series ended each episode, for the first several seasons anyway, with a climactic sword fight, decapitation, and lightning storm. Reaching this scene was often the whole point of the show—after all, it was the only way an Immortal villain could be stopped. But the writers deserve credit for including it no matter what, even in the occasional Very Special Episode that tackled real-world problems like sexual harassment.
 * Also, if you pick any three episodes, chances are that at least two of them will have an immortal whose name begins with a K sound. Sometimes it's the last name, sometimes the first name, sometimes it's a Q.
 * The medical team in House somehow manages to suspect lupus in every case. In the first season 4 episode, where House didn't have a team (at the end of Season 3, one was fired and the other two quit), a nearby janitor still managed to suggest a diagnosis of lupus, commenting after a brief stunned silence that his grandmother had it.
 * Lupus can imitate a whole rainbow of other diseases, and can be ludicrously difficult to diagnose; eliminating it from a list of possibles is a sensible move.
 * And let's not forget the first Lampshade Hang: in Season 3 House pulled some hidden Vicodin out of a hollowed out lupus text. When his team looks shocked House responds "Come on! It's never lupus." Even funnier was that in one episode, it turned out it was lupus.

"Marah: "What's the worst that could happen? They blow him up, we grow him big again, they blow him up again, we grow him big again, and they blow him and we grow him, and... Lothor: "I know the formula!""
 * Remember that House episode where he comes up with a theory but turns out to be wrong, then comes up with a second theory and turns out to be right?
 * More like, "Hey, remember that House episode where he comes up with a theory but it turns out to be wrong, then comes up with another theory and turns out to be wrong, then does something illegal or immoral, and then has another idea, and tests it in a way that would be fatal if he was wrong, but it doesn't matter because he's right?"
 * What about "Hey, remember that House episode where he's stymied and goes to do something totally unrelated to the case, during which an innocuous comment or action causes House to have an epiphany about the case which invariably turns out to be right?"
 * Someone dies at the beginning of every episode of Six Feet Under
 * Funky Squad: The Australian series parodied this trope—inevitably, there would be a brief zooming shot of the Funky Squad as they turned to face the camera, and most (if not all) episodes reminded the viewer that Ponch (apparently played by an actor who couldn't speak English—in reality Tom Gleisner, who speaks it fluently) couldn't speak as he had "taken a bullet to the tongue."
 * Monk does a The Summation every episode, often including the phrase "If I'm right... which... I am" and always including the phrase "Here's what happened" to the point that other characters state their desire to say "Here's what happened."
 * Subverted when a garbage strike had driven Monk (more) insane. He proceeded to rattle off an explanation of why Alice Cooper killed the mayor to steal his high backed chair, based solely on Cooper sitting in a high back chair in a poster and him being a "dirty hippy", done in the same black and white footage as the usual real events. Everyone just looks at him in stunned silence, until Randy asks "Should I be writing this down?"
 * Petrocelli had this too. In every episode, his client was wrongly accused on the grounds of seemingly conclusive proof. Once in court, the accusation would narrate the supposed events and then (and only then) he would offer his own version of what had happened. Invariably, this was the truth, and his client was declared not guilty.
 * "Mork, what Earth concept have you misunderstood this week?" (an actual Lampshade Hanging from the show.)
 * Power Rangers—except on the somewhat rare occasions when the Rangers use their own Finishing Move, the monster gets city-sized, and the rangers have to use their zords to defeat it. Interestingly, it never seems to matter how badly the monster gets beaten/shot/exploded/melted/punctured/vaporised/redecorated when it's human sized, it will always become perfectly healthy again when it's bigger.
 * That's one of the things that changes each season... some seasons the Big Bad makes the monster grow when he/she desires, or the monster does it itself, but in some seasons, the customary reaction to the human-sized monster's total destruction is to reassemble it into giant form (this is more common in the magic-based series.) Still, you get instances like Kilobyte, a Dragon in Power Rangers RPM: we see him blown into Ludicrous (Robot) Gibs... and immediately cut to him falling on the ground intact, standing up, and angrily saying the growth command.
 * It was Lampshaded in one episode of Power Rangers Ninja Storm. When one of the members of the Terrible Trio asked the Big Bad what should they do, he answers something among the lines of: "Make him grow up, of course! How many times have we done that? Didn't you catch it up yet? The rangers destroy the monster, we make the monster grow!"
 * Another time:

"'Allo, 'Allo, zis is Night'awk/Mrs Night'awk/Night'awk's muzzer-in-law."
 * Remember that episode of Smallville where Clark goes in to save the day, only to be inadvertently foiled by kryptonite?
 * With everyone randomly carrying around spare pieces of green rocks, it's amazing that Clark is ever able to use his abilities, let alone save the day.
 * Remember the episode where Clark can't find the bad guy until some missed clue shows itself and Clark rushes in and saves the day in under a minute and the remaining 9 minutes of the episode is devoted to different characters arguing about philosophy?
 * I think that was every episode of the 1950s Adventures of Superman, too...
 * Especially in the first season, the show seems particularly fond of having car crashes/accidents each episode.
 * MythBusters
 * The Hard Work Montage.
 * Something will be destroyed. Ranges from "having a frozen turkey dropped on it" to "hit with a car" to "scattered across a two hundred metre radius" to "requires the FBI's supervision, a truck full of TNT and a one-mile radius clearance around the blast zone".
 * Kenan & Kel
 * The long, drawn-out routine about Kel's love of orange soda.
 * Kenan's requests for Noodle Implements at the end of each episode and Kel's frustated reactions.
 * All That: Stage manager Kevin's Catch Phrase: "Five minutes! Five minutes until the show starts!" And then, Kevin getting abused somehow. For all six seasons.
 * Police Squad!: So much so that the series would have surely collapsed under them if it had been on for longer. Dreben parks his car and knocks over some trash cans (one more each episode); Al, who's too tall to fit in the frame gives Drebin and the Chief some information and they remark on some oddity of his appearance; Drebin bribes Johnny the shoeshine guy for information, who then gets bribed by a B-list celebrity; the elevator stops at some odd places, and a multitude of CatchPhrases ("Cigarette?" "Yes, I know." "Well.")
 * And how could we forget the guest start of the episode getting killed in some gruesome way before the actual start of the episode?
 * Not to mention the written and verbal reading of the title being completely different to each episode.
 * And the literal freeze at the end of the episode.
 * Or the villain of the week joining all the criminals caught in the previous episodes in jail. And each of them will be named.
 * In Psych, just about every episode features a pineapple, to the point where the advertisements for some episodes advertise a sweepstakes: Find the pineapple.
 * Also, almost every single episode starts with a flashback to the late '80s (nowadays, it's to the early '90s), showing Shawn as a child either having an experience that is materially or thematically related to the episode at hand (present!Shawn usually recalls this incident during the episode's events), or being taught a lesson (a bit of advice, a technique, a trick, etc) by Henry that, in the present day, explains where Shawn got the know-how to solve the episode's featured case. Sometimes subverted: for example, in "Shawn Takes a Shot In the Dark", the flashbacks are interspliced with the present-day story, guiding the audience so that we figure out Shawn's thought process along with the characters tracking him; and in "Shawn Rescues Darth Vader", the flashback comes at the very end of the episode to explain  earlier on, because if it had been shown at the beginning, all the suspense of the moment would have been killed.
 * Twice per episode of The Incredible Hulk, David Banner would transform into the, er, Incredible Hulk. It always happened about twenty minutes in, and then again right near the end of the episode.
 * I Love Lucy: Desi Arnaz's singing.
 * Home Improvement episodes often had Wilson imparting some words of wisdom to Tim, who then tries to repeat it to another character but mangles it into complete nonsense in the process. Some later episodes would have the other character respond along the lines of, "You've been talking to Wilson, haven't you?"
 * Don't forget Al: I don't think so, Tim.
 * Cheers -- "Norm!"
 * Almost every episode of iCarly has the group doing the webshow at least once. Only two episodes have not. iBeat the Heat and iLove You.
 * The Closer: Brenda loses her battle with sugar and manages to offend somebody.
 * Every episode of Alarm Fuer Cobra 11 has at least three chase scenes: one as (or shortly after) the Cold Opening, one in the middle, and one at the end. If a Chase Scene involves motor vehicles, expect a lot of Stuff Blowing Up.
 * In Kamen Rider Kabuto, Tendou Souji has to spout an allegedly wise quote from his grandmother once every episode.
 * The Dukes of Hazzard always has a car chase that ended with the General Lee jumping over a conveniently placed ramp to escape pursuit.
 * Allo Allo is more or less a collection of Once an Episode jokes and situations glued together with a thin film of plot. By later series, there were so many that they wouldn't all fit into every single episode... Examples include, but are by no means limited to:
 * Crabtree entering and saying 'Good moaning' (after season 2), prefaced by someone (usually Yvette) saying something along the lines of "'Ere comes zat English idiot 'oo sinks 'e can speak French."
 * Leclerc entering in a terrible Paper-Thin Disguise, and revealing himself either by lifting his specs or ripping off his fake 'stache to reveal his real one, with the line "It is I, Leclerc."
 * Michelle of ze Resistance entering, telling the cast to "Listen very carefully, I shall say zis only once."
 * Gruber hitting on Rene.
 * Rene hitting on the waitresses.
 * Rene getting caught by his wife whilst hitting on the waitresses, and coming up with a paper-thin excuse which she (usually) buys entirely. Always prefaced with "You stupid woman!"
 * Cross-dressing of one sort or another, usually in the form of Paper Thin Disguises which are usually damn near impenetrable.
 * The British airmen popping out from wherever they've been hidden this time, and saying "Hello!" in a strong English accent, and being incomprehensible to the French characters.
 * Mme. Fanny being lifted up in her bed to reach the radio. After season one, this scene would inevitably also include ze flashing bedknobs.

"Ben: My favourite episode was the one where Bud was gonna have sex with a really hot girl and then it didn't work out in the end. David: I think that was episode... 50, 75, 80... Will: I really missed that episode because I was watching that episode of House where they couldn't figure out what the disease was. David: I was watching the episode of Three's Company where they thought they heard something different. Ben: I'm on the episode of McLeod's Daughters where a handsome stranger comes to town."
 * Some form of Benny Hill-esque chase sequence, usualy closing out the episode.
 * Someone mentioning the painting of ze Fallen Madonna wiz ze Big Boobies by Van Clomp.
 * The elaboration of a near-incomprehensible plan/retelling of the plot so far, involving multiple copies of multiple paintings to be kept by multiple people to sell after the war, various hidden secrets and affairs, and lots of innuendo.
 * Top Gear:
 * Crazy ideas with the precursor, "How hard can it be?". Afterwards: "That's not gone well".
 * Jeremy Clarkson ending every episode with "...and on that bombshell..." As well as some variation of "The most powerful/fastest/biggest etc... in the world.
 * The "Some say" build-up whenever the Stig is about to appear. "Some say all his potted plants are called Steve, and he knows two facts about ducks -- both of which are wrong."
 * Every episode of Scrubs has some variation of the line, "And there it is."
 * Whose Line Is It Anyway?: Drew's Catch Phrase, "Everything is made up and the points don't matter," followed by a statement (usually a Take That) that shows how worthless the points are.
 * "Everything is made up and the points don't matter. That's right, the points are like notability on TV Tropes."
 * "Everything is made up and the points don't matter. That's right, the points are like all the hours you spent on TvTropes."
 * Every episode of The Amanda Show on Nickelodeon starts with Amanda Bynes coming on stage to introduce the show, but something bizarre always goes wrong in the studio and she has to apologise and say they'll sort it in a few minutes, cutting to pre-filmed items or commercials.
 * Lost has about every episode someone claim that "he/she/they/we/it is/are/were lost" (with the occasional "have you lost your mind?". They also steal the "bad feeling about this" line from time to time, most notably.
 * Sawyer exclaims "Son of a bitch!" at least once in almost, if not literally, every episode he appears in.
 * Also, Ben gets beat up to such an extent that Michael Emerson's answer to "how many times has Ben been beaten up?" was "how many episodes have I been in?"
 * Pick three episodes of Star Trek: The Original Series. Now watch them. The odds are pretty good that in two out of those three, Kirk's shirt will be utterly destroyed... and with good reason.
 * Lampshaded in Galaxy Quest, where The Spock tells The Kirk "I see you managed to get your shirt off."
 * From the fourth season of Star Trek: The Next Generation on, the number 47 is hidden somewhere in almost every episode of the series.
 * Harry Hill's TV Burp: "Now, I like (x), and I also like (y). But which is better? There's only one way to find out.... Fiiiight!"
 * The Danish Christmas calendar series Christmas on Vesterbro has several of these:
 * Stewart Stardust reminisces about his father speaking words of wisdom and beating Stewart.
 * Stewart opens his package calendar and is mock-surprised to find a beer.
 * Someone opens the door to Vivian Stardust's room, causing her to scream "GO AWAY".
 * Criminal Minds: Every episode (except the second parts of two-parters) begins with a quote delivered in voiceover, and most end with one as well. Also, every episode has the team deliver the profile of the offender to whichever group of police/other FBI agents they're working with, although this is averted in "True Night", which focuses so heavily on the killer that the briefing is missed by the audience, though it does occur (as can be seen by the details on the whiteboard when the killer is brought in).
 * Ever Decreasing Circles: Martin turning the phone around.
 * Made in Canada (syndicated globally as The Industry) would have one of the main characters making an aside statement of "I think that went well" or "This is not good" to end every show. Every. Last. Show. For six seasons.
 * The X-Files: Scully and Mulder-centric episodes feature Mulder suggesting something supernatural is going on, Scully responding with Arbitrary Skepticism, and proving it's absurd "scientifically." Mulder is almost always right. Scully never admits it. Mulder actually lampshades this in season 6's "Field Trip".
 * Also, Mulder doing/saying something that makes Scully feel uncomfortable.
 * Mulder asking Scully to do something and her responding with "What are you going to do?"
 * Especially from season five onward, somebody making the assumption that Mulder and Scully are romantically involved.
 * On the New Zealand show 7 Days they make a string of jokes about this with Married... with Children star David Faustino.

"Jesse: I'm just trying to think of another one."
 * Then:


 * The "Brainstorming" song shows up at least once an epsiode on "Imagination Movers"
 * CSI: Miami: Horatio Crane puts on his Cool Shades, does the Quip to Black and bam, we get the Metal Scream by The Who.
 * The entire CSI franchise has Red Herrings every single episode.
 * On CSI the original, DB will mention his wife. And he'll either call her or she'll call him.
 * CSI: NY Danny will say "Boom!"
 * Fawlty Towers: The sign outside the titular hotel has the letters rearranged in most, if not every, episode.
 * All except one IIRC.
 * Ramsey's Kitchen Nightmares:
 * Gordon changes his shirt on screen.
 * Gordon cusses his bleedin' head off.
 * Gordon changes his shirt and cusses his bleedin' head off.
 * Gorden cusses his bleedin head off, changes his shirt and cusses his bleedin' head off.
 * The Sarah Jane Adventures: Luke and Sarah Jane are separated by some force beyond their control, and this will piss Sarah Jane off. Sometime in the last ten minutes, they will be reunited with an incredibly heartwarming hug, and Sarah Jane will tell whoever tried to mess with him something along the lines of "Go to Hell before I send you there myself."
 * David Mitchell will launch into a Character Filibuster on Would I Lie to You? (more often than not with the provocation of Lee Mack).
 * Just about every single episode of Seinfeld contains at least one reference to Superman.
 * The Hard Times of RJ Berger has an animated sequence in nearly every episode, the majority of them being flashbacks.
 * Law and Order: Criminal Intent: The detectives will use a Batman Gambit to push the murderer into having a Villainous Breakdown.
 * In Fringe, there are two proeminent ocurrences:
 * The Observer, his appearances are often Freeze Frame Bonuses.
 * Also, there's always a specific phrase, or object, background prop, etc that foreshadows something in the next episode. Sometimes they are so specific that the hint only gets clear after watching the next episode.
 * In the Britcom Chance In A Million the coincidence-prone title character Tom Chance (Simon Callow) drinks an entire pint of lager in one go, usually in mid-sentence. Sometimes this happens more than once per episode, on at least one occasion twice in rapid succession, and once together with a guest cast member. (Actually they used trick glasses holding much less than a full pint).
 * "Live from New York, it's Saturday Night!" Also Weekend Update.
 * Hill Street Blues would open every episode with the daily briefing by the Desk Sergeant, inevitably closed with him telling the officers, "...and hey! Be careful out there!"
 * In every episode of Danger 5:
 * The Danger 5 team gets a mission briefing from the Colonel, who gratuitously insults Claire.
 * Ilsa gets brainwashed by the enemy and attacks at least one of the good guys.
 * Hitler escapes from the team by leaping through a glass window.
 * On Laverne & Shirley, David Lander (Squiggy) got so sick of having to say 'Hello' over and over that he refused to say it anymore. The producers reached a deal with him in which the writers were only allowed to have him say it Once Per Episode.
 * The same thing happened on Hunter with the title character's Tagline "works for me."
 * Harvey Korman appeared briefly as a Soviet bureaucrat at the end of every episode of the 1976 Sitcom Ivan the Terrible.

Literature

 * Death turning up in Discworld. He has at least one cameo in every book. Except for "Wee Free Men" the one book that is actually all about bereavement. Go figure.
 * Animorphs There will be a meeting in Cassie's barn

Music

 * Old Crow Medicine Show seems contractually obliged to record at least one song about drugs per album.
 * Metallica, Dragon Force (video game) and quite a few other Metal artists seem to have a "one ballad per album" rule.
 * Type O Negative had at least one Cover Version per album on every album apart from Slow Deep And Hard and Dead Again. (the rerelease of Slow Deep And Hard features their cover of Hey Joe (Called Hey Pete) as a bonus track, however)
 * Iron Maiden had one or two epics per album until they decided to make every song on the album an epic from A Matter Of Life And Death onwards. They would also make sure to have at least one historical song named after a war film.
 * Fun-Lovin' Criminals admit they have to include at least one 'stoner jam' on each album (the song they were referring to was Rewind from Classic Fantastic)
 * Crowded House claimed to have included a reference to a kitchen on every album.
 * All of The Beatles albums have a track where George Harrison sings lead (mostly the ones he wrote) and all but two have one track allowing Ringo Starr to Step Up to the Microphone.
 * All the Garbage albums end with a depressing ballad.

Newspaper Comics

 * Little Nemo: Nemo wakes and falls out of bed in the last panel of each of Winsor McCay's Little Nemo's Adventures in Slumberland comic strips.
 * Krazy Kat: Ignatz Mouse attempts (with varying degrees of success) to acquire a brick and hurl it at Krazy Kat. (Okay, this only happens in maybe 75% of the strips, so maybe it should go under Running Gag.)

Radio
"Humph: When music experts hear Colin's compositions, they say he could have been another Berlin, Porter, or anybody else employed by the German State Railway."
 * I'm Sorry I Haven't a Clue featured many, including the game Mornington Crescent (usually preceeded by reading a fan letter from Mrs Trellis) and the introduction of the pianist Colin Sell:


 * In Old Harry's Game the majority of episodes will have the Professor and Satan making a bet, most commonly about morality and something bad would happen to Thomas.

Video Games
"Maya: "Look, a ladder!" Phoenix: "That's a 'step'-ladder." Maya: "So? What's the difference? You need to stop judging things based on narrow-minded cultural assumptions, Nick!" Phoenix: "R-right... sorry. (This girl is out there!)""
 * In the first two Halo games, a character says something along the lines of "I've got a bad feeling about this" and then a character says "you've always got a bad feeling", right before the first appearance of the Flood in that game (itself a reference of Star Wars).
 * The "Siege of Madrigal" Easter Egg has appeared in all main games so far.
 * Each game in the Ace Attorney series has a stepladder that can be examined. If it is examined, the following exchange will occur, with the words in parentheses varying each game:


 * The Dark Cloud series is made of Once Per Episode formula.
 * Atlamillia(s)
 * Destruction of the Western Continent.
 * Dialogue: "So, you hate me too." First said by, then by.
 * Stable Time Loop
 * Time Travel
 * Metal Gear: It seems that Dave Hayter must say "Metal Gear?!" in an exasperated fashion once per game. Additionally, someone Otacon cares about must die.
 * The player getting tortured counts as well.
 * There's also Snake's pose after landing on the tanker at the start of Metal Gear Solid 2: Sons of Liberty, which two different characters end up copying at some point in every other main-series game afterwards.
 * Revolver Ocelot mentioning in some sort of fair detail why he believes his weapon of choice is by far the greatest creation in all of human history.
 * Final Fantasy has several. Some are absent in early installments, but once they are introduced, they always appear in each game afterward.
 * There is always a Global Airship.
 * Someone associated with the game's Global Airship will be named Cid.
 * There will be a pair of characters named Biggs and Wedge.
 * Giant, flightless yellow birds will always be the animal mount of choice.
 * BioShock (series) has a single dead cat in every room. The sequel has continued the tradition.
 * Monkey Island: Guybrush Threepwood always seems to come across The Voodoo Lady right when he needs her, and Stan right when he doesn't.
 * The God of War series has A) Kratos getting sent to Hades, B) a Hot Coffee Minigame, and C) Kratos screaming someone's name (usually his enemy's) at the top of his lungs.
 * ZEUUUUUUUUS! You LIED to me!!!
 * Pretty much every Pokémon game has one fisherman who fights you with 6 low leveled Magikarp.
 * Played with in Pokémon Black and White, where that one fisherman's Magikarp are level 60, which is LONG after they should have evolved into Gyarados.
 * Every game set except for the Generation I group has had a Youngster Joey.
 * Every stage in Timesplitters: Future Perfect, except the first and last, has a rambling drunk person in it somewhere.
 * Ever since the third Guitar Hero game, there has been a Muse song in the setlist of every main game in the series.
 * Every Call of Duty game set during World War 2 has at least one mission where you get to control a tank.
 * Every Call of Duty game developed by Infinity Ward includes a Captain Price. The Anachronic Order present by virtue of having multiple games set during World War 2 means they can do this even though Price died in the first game.
 * Every game in the Saints Row series has at least one named ally die over the course of the game, with the player having the ability to bring them back as a zombie later on.
 * Every Mass Effect game has a Point of No Return event disguised as a seemingly unimportant or easily accomplished request given to you.
 * Every game in the Saints Row series has at least one named ally die over the course of the game, with the player having the ability to bring them back as a zombie later on.
 * Every Mass Effect game has a Point of No Return event disguised as a seemingly unimportant or easily accomplished request given to you.

Web Comics

 * A failed version of this is in Concerned. According to the notes of the artist, he was planning to "have a bunch [of barrels] around in every comic after Frohman mistakenly ordered them." Unfortunately, he stopped doing so three comics later.
 * Moru from God Mode used to wear a different video games related hat every page... until Adis ruined it...
 * In every story arc of The Inexplicable Adventures of Bob, something very big will crash into Bob's roof, producing vertical block letters spelling "BOOM!"

Web Original
"Eh! Steve!: "Eh! Steve!""
 * EPICMEALTIME: "Next time, we eat x!" where x is something outlandish or impossible to eat, but subverted in The Slaughterhouse: "Next time, we eat dessert!" Sure enough, next week was The Black Legend: two girls eating a gigantic crepe.
 * Phelous dies once per episode, granted there seem to be one-ups roaming around his house, and something to do with Time Travel or cloning or the fact it might be partially in the Mortal Kombat verse oh I give up, I don't know.
 * "Hey Troper!" "What?" "Knife."
 * Parodied in Homestar Runner, where Strong Bad specifically says that Once an Episode of Sweet Cuppin' Cakes, Eh! Steve! shows up to deliver his Catch Phrase.

Western Animation

 * Bugs Bunny has his "Eh, what's up, Doc?" line, occasionally varied depending on who he's addressing (e.g., "What's up MacDoc?" to a Scotsman, "What's up croc?" to a crocodile, "What's up duck?" to Daffy Duck).
 * South Park
 * The death of Kenny in early seasons.
 * Cartman's "Screw you guys: I'm going home."
 * The semi-faux-moralising summation from one of the kids, starting with: "You know, I think I've learned something today..."
 * Pinky and The Brain
 * Every episode has a Are You Pondering What I'm Pondering? exchange, and ended with "What are we gonna do tomorrow night, Brain?" "Same thing we do every night, Pinky... try to take over the world!"
 * They hung a lampshade on both of these several times. In one instance, Pinky asks Brain if he has ever been pondering what Brain is pondering, and decides that no, he never has (Which, in fact, was exaactly what Brain was thinking), and in several instances, Brain's plan was to "Find a better hiding place", "Take over Chia-World", and "Take over the Globe...theater."

"Pinky: I've seen every episode of Gilligan's Island! Brain: Oh really? Did you see the one where Gilligan screws it up for everyone? Pinky: ...No, I don't think I've seen that one..."
 * Pinky And The Brain Lampshades the Once Per Episode escape attempts on Gilligan's Island.


 * The ending pattern was averted only once. When Pinky was rendered intelligent via one of Brain's inventions, Brain realized that one of them needed to be stupid to maintain the proper dynamic. Seeing that Pinky was better at being smart than he was, Brain made himself stupid. Unfortunately, Pinky felt bad about upstaging Brain and had already made himself stupid again. Both of them were stuck being idiots because neither of them had the intelligence to operate the machine again. The episode ended with "What are we gonna do tomorrow night, Brain?" "...I have no idea."
 * The Legend of Zelda:
 * Link's Catch Phrase "Well, Excuse Me, Princess!!" in the cartoon. In this case, it's at least twice per episode, three times if you count the opening.
 * Link's dogged attempts to get a kiss, which Zelda always found a different excuse to reject. (Anyone else wonder why she couldn't just say "No?" Judging from the way she treated him the rest of the time, she certainly wasn't worried about hurting his feelings.)
 * She actually did accept when she did realize Link was a ghost, causing him to go right through her.

"Dukey: I know I know! You 'didn't see that coming' either!"
 * Then when she truly accepted during a picnic trip, they were interrupted by a monster attack.
 * Transformers: Beast Wars: Waspinator being beaten and battered, usually in a slapstick manner. In multi-part episodes such as "The Agenda", this would happen in each part.
 * Transformers, in every episode that Starscream appears in, he attempts to overthrow Megatron, and fails.
 * "You've failed me yet again Starscream."
 * "My time will come Megatron!"
 * In Jem, they are least two Jem songs for one Misfits in a normal episodes.
 * The Catch Phrase "Didn't see that coming." is uttered by someone in each episode of Johnny Test. That's episode as in each 15 minute episode, so it's said twice in each half hour "wrapper episode."
 * Lampshaded in the Incredible Shrinking Man episode.

"Ray: Sorry, Sweet Little Granny, but this timeslot is needed urgently!"
 * Adventures of Sonic the Hedgehog: "I hate that hedgehog!"
 * Birdman's catchphrase on the show of the same name: "Biiirdman!", worked in two or three times per seven-minute episode. To add "Birdman is captured by the villain and saved by Avenger" and "Birdman is caught in the dark and deprived of his powers" to the list would be only mild exaggerations.
 * And in "Harvey Birdman: Attorney at Law", "I'll take the case!" was uttered in every episode.
 * Did you get that thing I sent you?
 * I couldn't hear that! I only have the one eye!
 * Scooby Doo:
 * "And I would have gotten away with it too, if it wasn't for You Meddling Kids."
 * Also, musical chase scenes
 * Also, scooby snacks
 * Also, "Let's Split Up, Gang!"
 * Was "Jinkies!" "Velma said 'Jinkies!' It must be a clue!" only in the spinoff A Pup Named Scooby Doo, or what?
 * Also, one that was was Freddy having to accuse Red Herring of being the villain.
 * Ironically, during the one episode when Freddy promised to not accuse Red of anything, . Pretty bad timing, wasn't it...
 * Nearly every episode goes like this: they're all riding the Mystery Machine, Scooby steals Shaggy's sandwich, the gang stops somewhere and are warned of a ghost, all but Scooby and Shaggy are convinced that it is a silly superstition, Fred suggests they investigate and split up so he and Daphne can go off-camera, the ghost terrorizes Scooby and Shaggy when they ditch Velma to obtain food, no one believes them, the ghost terrorizes Scooby and Shaggy again and Velma is there but she cannot see anything due to her glasses being knocked off, eventually she finds her glasses and the ghost terrorizes everybody, they are scattered in a silly montage, they regroup and Fred comes up with a trap of some sort, the trap requires Scooby and Shaggy to be used as bait with a bribe of Scooby Snacks, the ghost is caught and revealed to be a person chasing people away for financial gain of some sort.
 * And they always screwed up the trap somehow. Luckily, the screwup always caused the villain to get caught, just not in the way everybody was hoping for.
 * The Scooby Snack bit is lampshaded in one of the What's New Scooby Doo episodes where Shaggy admits that there's nothing he and Scooby wouldn't do for a Scooby Snack. Another episode also lampshaded the splitting-up - Fred merely suggests they do so, Scooby and Shaggy immediately begin to walk off, and when Fred points out he didn't say how they'd split up, Shaggy asks him "Like, do we ever do it any other way?"
 * Futurama: "Good news, everyone!". Inverted a couple of times as "Bad news, no one!" Specifically, in the episode with the Ikea Particle Accelerator.
 * Road Rovers had Hunter's "I would not have predicted this!" in response to some new development.
 * The Secret Show has three of these.
 * Every episode starts off with half a minute from "The Fluffy Bunny Show", hosted by Sweet Little Granny. Unfortunately, Granny never gets to finish her theme song, as Agent Ray interrupts and removes her and her bunnies from the set

"Professor: Victor! Are you still alive? Victor: Yes I'm still alive!"
 * The director of Uzz -- "As You Know, for reasons of security, my name is changed daily. Today you may call me-- " He checks his communicator and sighs sadly, before announcing that his name is "Fluffy-fuddlesticks" or "Bopybot" or something equally ridiculous.
 * Professor Professor calling to check in on Victor, always resulting in the following exchange:

"Perry sneezes. Phineas: Bless you, Perry the Platypus!"
 * Usually happens while Victor is trying to quietly sneak around some bad guys, hanging from a ledge above a long drop, or surrounded by monsters. And, more often then not, immediately after falling from said ledge or being pummeled by monsters.
 * Phineas and Ferb, a Disney cartoon about two step-brothers and their summer exploits, has like a dozen of these. Part of the humor is seeing how they subvert and invert each of them in new episodes, whether said by different characters or in different phrasings. Some include:
 * Phineas telling Ferb "I know what we're gonna do today!"
 * Isabella showing up to say "Hey Phineas. Whatcha doooin'?"
 * Phineas saying "Hey, where's Perry?" And at the end of the episode, "Oh, there you are, Perry!"
 * Someone asking Phineas and Ferb "Aren't you a little young to be filling-in-the-blank?" Phineas usually responds with "Yes, yes we are,", though he answered "No, I don't think so," in "Flop Starz". Phineas and Ferb: subverting its running gags since episode 3
 * Played with again when the question is posed by a delivery-man in "Spa Day", and answered with quite more irritation than Phineas ever exhibits by another delivery-man, who then aplogizes to Phineas and explains that the first guy is new on the job.
 * Candace threatening to tell mom about Phineas and Ferb's latest crazy project.
 * Dr. Doofenshmirtz shouting "Curse you, Perry the Platypus!" after being thwarted.
 * Which was inverted in "Hail Doofania!", just like every other Once Per Episode occurrence.

"William Conrad: Be with us next time for Fill-In-The-Blanks or Mad Lib!"
 * Also inverted by Vannessa in "Dude, We're Getting the Band Back Together!" after Perry helps arrange her sweet sixteen party. As Perry blast off, she calls, "Thank you, Perry the Platypus!"
 * Each episode has at least one original song.
 * Ferb says at least one but no more than three lines per episode, a la Silent Bob. He managed to get an impressive inspirational monologue in "The Lizard Whisperer", though.
 * Doofenshmirtz makes a new evil device every episode.
 * ...the name of which ends in -inator, sometimes taken to ridiculous extremes (like the "Gloominator 3000-inator" from "Leave the Busting to Us"). There are exceptions: in "Mom's Birthday" Doofenshmirtz created the Shrinkspheria ("I was going to call it a Shrinkinator, but I've done the whole 'inator thing before"), and some of his inventions don't have the suffix at all, like his mind-controlling termite helmet in "The Magnificent Few" or the BO-AT from "Interview With a Platypus".
 * ... that gets destroyed/disabled/stolen by Perry, often using a self-destruct or reversal dial included on the device.
 * ... but not before somehow removing the latest Phineas and Ferb contraption with it, seconds before Candace can show the evidence to their mother, regardless of size.
 * This doesn't occur each episode, usually because the boys already made it disappear on their own by giving it away (such as a monster truck arena) or it disappeared on its own (such as a giant soap bubble bursting.) Regardless, it is gone before Candace can show it to her mother.
 * After receiving his summons, Perry will exit the stage using a different secret entrance every episode.
 * The "Doofenshmirtz Evil Incorporated!" jingle always plays over a shot of Doofenshmirtz's lair
 * Perry is always caught within seconds of arriving on the scene of Doofenshmirtz' latest plan.
 * Doofenshmirtz will always explain the reasoning behind his latest device soon after, which usually involves some petty grievance, frequently from his youth.
 * You can bet on two things in any Eek! The Cat episode. 1) Eek will always say "It never hurts to help." 2) It will always hurt to help.
 * Also in the sub-cartoon "The Terrible Thunderlizards", Bill will say "When does the hurting stop?"
 * Also in the Thunder-Lizards, one of the Lizards themselves, if not someone else, will make a reference to the Bad Things Category. Most memorable example, in a flashback to their school years: "Yes, Cutter. I'd say having our little friend's head ripped off by the Principal would definitely fall into the Bad Things Category."
 * Rocky and Bullwinkle: "That voice. Where have I heard that voice?"
 * And the companion line: "Allow me to introduce myself!" followed by Boris handing Rocky a pre-printed business card with his nom du episode on it.
 * Although this happens once per ending, the episode titles as presented by the narrator should not be forgotten.


 * In Inspector Gadget, Chief Quimby somehow gets blown up by his own exploding message to Gadget...no matter where he is.
 * "I'll get you next time, Gadget! Nneexxtt Ttiimmee!"
 * At least once per episode sometime bad will happen to Eustice at the end of each episode of Courage the Cowardly Dog; he will either get killed, locked up, or severely injured.
 * Jonesy acquires, and is fired from, a new job in just about every episode of 6teen.
 * Near the beginning of every Kim Possible episode, Kim gets a page from (or, more rarely, pages) Wade on her Kimmunicator. Usually accompanied by the words "What's the sitch?"
 * Woody Woodpecker: Woody's laugh. Subverted in that occassionally someone else performs it, usually to mock Woody (cf. "Well Oiled", "The Coo-Coo Bird"). If Woody loses he will sometimes do a pathetic whining variant (as in "The Clip Joint").
 * In every episode of Thundercats, several things can be counted on to happen:
 * "Ancient Spirits of Evil...transform this decayed form...to Mumm-Ra! THE EVER-LIVING!" (at least in every episode featuring Mumm-Ra as an antagonist, which was most of them)
 * "Sword of Omens, give me sight beyond sight!"
 * "Thunder... Thunder!... Thunder!... Thundercats, HO!"
 * Even in the Freaky Friday episode they manage to get the Thundercats cry in.
 * In Earthworm Jim, at the end of each episode, a cow falls on something (a great many variations on this one).
 * Example "nothing can ruin the tenderness of this moment. Nothing. Hello? [impatient] I said nothing, not even a giant cow falling on me..."
 * The show also had a once-per-episode (or very close) gag of Peter Puppy eating haggis and reminding viewers that it is "the heart and lungs of a sheep boiled in its own stomach."
 * Just about every episode of Duckman has the titular character commit some horrible atrocity on his office assistants Fluffy and Uranus. Since they are living plush toys, they automatically recover.
 * Animated cartoons made by Jumbo Pictures/Cartoon Pizza typically have a song that is featured in each story. In PB and J Otter it was the "Noodle Dance," in Stanley it was "The Great Big Book of Everything" and in Pinky Dinky Doo it's "Story Box."
 * Butch Cassidy and the Sundance Kids: Elvis somehow finding his way into the briefing room and triggering Mr Socrates' Sneeze of Doom.
 * In just about every episode of the Aqua Teen Hunger Force the television ends up destroyed.
 * Lilo & Stitch: The Series. The fat bald guy never quite gets to enjoy his mint chocolate chip ice cream.
 * KaBlam!! had tons of these. One includes Henry and June dancing during the opening number (except one episode due to a longer commercial break) and then jumping up to the top comic panel, while Henry or June says, "Howdy KaBlamoids!" or "Welcome back cartoon crammers!" and then the duo would introduce themselves.
 * Another one would be June pulling some sort of prank on Henry. From mimicing him, randomly bleeping out what he's trying to say, ect.
 * Another would be in Life with Loopy where Larry would say, "Hi, I'm Larry. This is my sister Loopy, and this is (insert main idea of episode)". Starting season two, he'll say, "Hi, I'm Larry. (Insert main idea of episode)".
 * Also, in Prometheus and Bob, Prometheus will try to teach Bob something, but the monkey will always mess him up.
 * Action League NOW had a bunch of these, too (not surprising as it's a KaBlam!! spin-off. One would be Meltman always getting hurt.
 * Or The Cheif saying, "Blast it!" and sometimes "Blasted!".
 * And Bill the Lab Guy saying "There's nothing I can do." or "Oh, no. I was afraid of this!".
 * Stinky Diver saying, "Blimey!".
 * The Flesh saying "Ouchies!".
 * At least once in every episode of Family Guy one character says "What the hell?" (or in Stewie's case, "What the deuce?") to another.
 * In every episode of Jimmy Neutron, Jimmy screws something up that is threatening to the entire town and thinks of a way to fix it. In every. Episode.
 * Daria: A promo for a show-within-a-show you hardly ever actually see? The once-an-episode gag was an avert for "Next on Sick, Sad World!"
 * At least once per short the "Gotta Zip" song pops up in Jungle Junction.
 * SWAT Kats: The Radical Squadron had Enforcer Commander Feral saying "This is Feral: Bring me chopper backup!"
 * This is actually very common in Pixar films. Here are some of the most notable examples:
 * John Ratzenberger is the only voice actor to appear in every single Pixar film. Here are all of the characters Ratzenberger has voiced:
 * The Toy Story series films: Hamm the piggy bank
 * A Bugs Life: P. T. Flea
 * Monsters, Inc.: Yeti the Abominable Snoman
 * Finding Nemo: The Moonfish
 * The Incredibles: The Underminer
 * The Cars series films: Mack the semitruck
 * Ratatouille: Mustafa the waiter
 * WALL-E: John the human
 * Up: Tom the foreman
 * Brave: ???
 * |The "Pizza Planet" truck, a rusty, beaten-up yellow pickup truck that appears in every single Pixar film, even in The Incredibles. Here are all of the truck's appearances:
 * Toy Story: The truck's debut. Serves as Woody and Buzz Lightyear's tranportation to the Pizza Planet restaurant.
 * A Bugs Life: Can be seen being parked outside of a trailer home.
 * |Toy Story 2: Can be seen being stolen by Andy's toys as an attempt for them all to get to an airport.
 * Monsters, Inc.: See the A Bug's Life example above.
 * Finding Nemo: Can be seen driving by at the end of the film during the scene where the Tank Gang finally succeed in escaping from the dentist's fish tank.
 * The Incredibles: Hardest to notice in this movie as all you really get to see of it is a pale blur in part of the Parrs' high speed return to the city, but it's there.
 * Cars: Is anthropomorposized and is given the name "Todd."
 * Ratatouille: Can be seen driving on a bridge way off in the background during the scene where Remy is chased by Skinner, but it's really hard for animation fans to spy this vehicle.
 * WALL-E: Can be seen among a trash heap at the very beginning of the film.
 * Up: Can be seen parked alongside a sidewalk during the scene when Carl Friedrickson's house flies away into the sky.
 * Toy Story 3: Serves as  and Big Baby's transportation to Sunnyside Daycare.
 * Cars 2: Todd makes a reappearance in this film.
 * Brave: Yes, they actually confirmed that the truck will appear in this movie despite taking place in medieval Scotland.
 * Also, A113 constantly appears in the backgrounds of all of the films (A113 is actually the name of the classroom most of the Pixar staff worked at at the California Institute of Art and Technology). Here are all of the appearances of A113:
 * Toy Story: The license plate on Mrs. Davis' minivan.
 * A Bugs Life: The barcode number on the cereal box used for a building for the insect city Flik visits in the film.
 * |Toy Story 2: A call number for LassetAir (a possible reference to John Lasseter) A113 is mentioned during the airport scene. Also, the aforementioned A113 license place makes a reappearance in the film.
 * Monsters, Inc.: A sign on the wall in the background during the scene where Sulley thinks that Boo got crushed to death in the trash compactor.
 * Finding Nemo: The model code on the camera the scuba divers used to stun Marlin just right after capturing Nemo
 * The Incredibles: The cell Mr. Incredible is held captive inside Syndrome's lair (floor A1, cell 13). Was also mentioned earlier in the film by Mirage.
 * Cars: Mater's license plate. Also, the number on Trev Diesel (the locomotive that almost hit Lightning McQueen on his way to Radiator Springs)'s headlights and running boards.
 * Ratatouille: The tag on Git the lab rat's ear.
 * WALL-E: Directive A113. Also, WALL-E's name.
 * Up: The sign in front of the courtroom Carl Friedrickson's trial was held for hitting a foreman attempting to demolish his house.
 * Toy Story 3: The A113 license place returns, but it's now on a hatchback instead of a minivan.
 * Cars 2: The number on Siddely (Finn McMissile's fighter jet sidekick)'s tailfin. Also, the A113 license plate makes a reappearance in this film along with Mater.
 * Brave: "ACXIII"
 * And just about every single Pixar film has at least one cameo of a future Pixar character.
 * Monsters, Inc.: Nemo.
 * Finding Nemo: Mr. Incredible.
 * The Incredibles: Doc Hudson.
 * Lifted: Linguini.
 * Ratatouille: Dug the dog.
 * Your Friend, the Rat: WALL-E.
 * Up |Lotso Bear.
 * Toy Story 3: Finn McMissile.
 * Cars 2: Queen Eleanor, Princess Merida, King Fergus, and the Royal Triplets as cars...
 * Air Mater: Skipper and Sparky (Not technically a Pixar film, but under Lasseter's watch).
 * The Fairly OddParents: The plot for every episode since mid-season two/season three to season six, with a few exceptions, can be summed up by one plan:
 * Step One: Timmy sees a recurring problem in his life.
 * Step Two: Timmy goes to Cosmo and Wanda and does a mini-rant, comes up with a "solution" that has to be be done with magic or would take too long and or he'd be too lazy to do, so then he makes the wish.
 * Step Three: Timmy, Cosmo and Wanda see how great the wish turns out for him or everybody(sometimes Wanda or Cosmo questions this, only to be shrugged off by the other two),
 * Step Four: The wish backfires. Timmy "has got to find Cosmo and Wanda to unwish that wish", but for some reason they are ether doing something of equal importance, or they can't undo it for some reason. can't unwish it,
 * Step Five: Timmy goes on a quest to unwish the wish. The wish gets undone,
 * Step Six: Timmy learns his lesson and makes a little speech about it.
 * In each episode of The Problem Solverz, the team will consult Tux Dog for advice on their case, and Roba will stamp someone with the "Problem Solved" stamp.
 * My Little Pony Friendship Is Magic:
 * Twilight Sparkle writes a letter to Princess Celestia telling her what she's learned about Friendship this week. Season 2 episode 3 actually invokes this, with Twilight going progressively more insane as she realizes that she hasn't learned any friendship lesson yet, believing that a failure to send in a report will get her kicked back to Magic Kindergarten. From the second season on, the reports are spread more evenly throughout the cast, and not quite in every episode.
 * Season 2 Episode 15 subverts it a different way; Applejack does the writing this time, and she writes, not to tell Celestia what she learned, but to brag to Celestia that she didn't learn a darn thing, because she was right the whole time and everyone else needed teaching.
 * In the second season, Derpy Hooves has a Where's Waldo type cameo in every episode.
 * Not quite every episode, but every episode in which Rarity has an appearance, the writers strive to ruin her perfect coiffure at least once.
 * The Disney Princesses actually cried at least once in their films:
 * Snow White and The Seven Dwarfs: When Snow White gets lost in the woods.
 * Cinderella: When the Ugly Stepsisters tear up Cinderella's pink dress.
 * Sleeping Beauty: When Aurora hears about her 16th birthday from the fairies.
 * The Little Mermaid: When King Triton destroys Ariel's belongings.
 * Beauty and the Beast: When Belle is forced to stay as the Beast's "prisoner", and during the Beast's "death."
 * Aladdin: Just right after Jasmine yells at her father the Sultan after an argument concerning arranged marriage.
 * Pocahontas: When Pocahontas discovers that John Smith is going to be executed for the alleged murder of Kocuom.
 * Mulan: After Mulan gets into an argument with her father about joining the war in his place, before deciding to disguise herself as a male soldier and go off anyway.
 * The Princess and the Frog: When Tiana is refused by the contractors from the construction of her future restaurant.
 * Tangled: During Flynn's "death."
 * Name one Good Vibes episode that doesn't include an instance of peeing and/or pooping.
 * Dastardly and Muttley in Their Flying Machines: STOP THAT PIGEON!!