Long Speech Tea Time

A character giving a long and involved explanation or speech glances over and notices his audience is distracted and busy doing something else, sleeping, or just deliberately waiting until the speaker shuts up. This mostly tends to happen when the Big Bad is all excited about telling the heroes his "evil" plan, only to find out that nobody cares or being interrupted and attacked.

Named for the typical gag shot of this trope, where the ignoring characters sit down and have some tea.

In America!, you're likely to hear Chirping Crickets instead. In comic format, likely to involve the Wall of Blather. Compare and contrast Pass the Popcorn (where the audience finds someone else's trouble entertaining) and The Snack Is More Interesting (where someone is directly involved, but acts strangely unconcerned).

Anime and Manga
"Lychee: Hey! I talking here!"
 * Happened on a semi-regular basis in The Slayers.
 * Also occasionally happens on Pokémon, usually when the Team Rocket trio are reciting their motto.
 * In one case, the main characters even twigged that they could use this time to rescue the 'mons.
 * In an early episode, Meowth makes a threatening monologue towards Ash's Pikachu, then finds that his fellow Team Rocket Pokémon (Ekans and Koffing) are ignoring him and having a tea break.
 * In an very early episode, a battle comes down to Ash's Metapod (a cocoon capable only of hardening itself to defend from attacks) and his opponent's. In the middle of this stalemate, the camera cuts to Misty in a bathing suit getting some sun. Those must have been some really dedicated trainers to not notice a girl changing clothes right next to them. But hey, Pokémon battles are Serious Business.
 * In a recent episode featuring Team Galactic, they easily set up and execute their counterattack in the length of time necessary for Team Rocket to deliver the motto.
 * Kakashi's typical response to Gai's impassioned declarations of rivalry is to glance up from his copy of Icha Icha Paradise and ask "Hmm? Were you saying something?"
 * In a recent episode of Zettai Karen Children, Mio called a Long Transformation Sequence Tea Time.
 * An episode of Ouran High School Host Club had the St. Lobelia girls making an impassioned speech... pan to the Host Club sitting on the couch, utterly bored. One of the twins is playing on a Nintendo DS.
 * In the Sonic the Hedgehog anime movie, Dr. Robotnik/Eggman gives a speech about how his robot generator is going to blow up if the heroes don't do something about it, then notices that everyone in the room, including Sonic, Tails, and even his own robots have fallen asleep.
 * In the last season of Sailor Moon a villain once escapes during the titular character's In the Name of the Moon speech, after getting frustrated from its length.
 * In Dragon Ball when Gotenks is fighting Super Buu inside the Hyperbolic Time Chamber, he spends a great deal of time giving a speech to his kamikaze ghosts. Piccolo then informs Gotenks of Buu, who is very nonchalantly sipping on an impressive looking drink while reading a magazine.
 * Happens repeatedly in Ranma One Half. Particularly effective in the first Non-Serial Movie, where it's basically a character trait (and Berserk Button) of the Chinese girl Lychee to deliver a heartfelt, sobbing tale of woe only to be summarily ignored.

Film
"Clive Candy: The Kaiser spoke, and the Prince of Wales spoke --
 * From The Life and Death of Colonel Blimp:

Barbara Wynne: Spoke about what?

Clive Candy: Nobody could remember."

Live Action TV

 * In the Frasier episode "Ask Me No Questions," Frasier is speaking to Martin, who gets up, leaves the apartment to fetch the paper, and returns just in time to absent-mindedly agree with whatever Frasier had been talking about, all without Frasier realizing. Later, the same thing happens when he's speaking with Daphne (she goes to catch up with friends and buy some coffee). Frasier is completely oblivious.
 * Doctor Who, "The Planet Of The Ood". When Donna steps out of the TARDIS and sees the awesome snowy vistas of the Oodsphere, her first impression is that it's bloody freezing. The Doctor encourages her to see the wider picture, appreciate the incredible views, consider how amazing it is that an average woman from Chiswick who was getting up, working, coming home, watching telly and going to bed is now travelling across space and time to land on alien worlds...and finds she's gone back into the TARDIS to get a coat.
 * In Top Gear, the characters had bought tractors and were having The Stig race them around the track to see which was slowest. They try to commentate on it for a minute or two, realize the futility of it all, and then give up to go have a tea break and discuss the weather.
 * Angel's speech about the virtues of humanity and how he'll fight to defend each and every one is interrupted by  Angel turns and asks him "Were you even listening?"

Newspaper Comics

 * In a Peanuts comic, Charlie Brown has the baseball team at his house for a meeting because it's raining out. He begins by running through their signals, but ends up launching into an inspiring speech about team spirit and the interest the players show in the game, only to turn around and find that everyone is watching his TV. The dialogue from the strip, slightly altered, was used for a more well-known gag in A Charlie Brown Christmas.

Theatre
"Hunter: I mean I don’t want this to be just sketches and novelty songs linked together. I want there to be substance, not just fluff. Not that there’s anything wrong with fluff, but I wanna strive for something that makes people really pay attention. You know what I mean?
 * from Title of Show:

Susan: Uh… I totally stopped listening."

Video Games

 * Kael'thas Sunstrider in World of Warcraft. Players died because they didn't realize he'd finally finished his speech and had started attacking them again.
 * This happens often enough that one of the more common mods has a timer to show how long until they shut up and fight. One of the bosses gained a common nickname; Lady Deathwhisper became Lady Talkstoomuch, for her two minute speech.
 * In Shadow Hearts: Covenant, one of the villains is giving a monologue about how the party is doomed, etc. However, he's doing this while sitting on a floating pillow, leading to the party discussing how the pillow floats. When he finishes, Yuri has only one question: "Where can I get one of those pillows?"
 * Yuri has a habit of interrupting people's monologue, usually to insult them.
 * In Mario & Luigi: Superstar Saga, Luigi not paying attention during some of the longer speeches was a Running Gag. He even drinks tea on several occasions.
 * Mario falling asleep in the Paper Mario series during long speeches is a Running Gag as well. Even his partners get in on the act in the sequel.
 * In Metal Gear Acid 2, before the boss battle with Metal Gear, Dr. Kopplethorn starts on a long, technical speech about how its nuclear missile works. Meanwhile, Snake tells Venus (and the player) what he's noticed about Metal Gear's weapons and how he thinks they should fight it, in speech bubbles rather than the standard text boxes. Once they've finished, Venus interrupts Kopplethorn with a lampshadey joke about the long speeches in the series, enraging him.
 * Amaterasu, the easily-bored wolf heroine of Okami, will lie down and take a nap at any idle moment, even if there's important Exposition going on. It really annoys Waka.

Web Comics

 * The end of a long exposition story in Order of the Stick.

Western Animation

 * Dr. Drakken gloats over his plan to lure out Kim Possible and blast her with his latest device, but then notices Shego leafing through the cable TV guide. "Trap for Miss Perfect, got it."
 * Shego does this all the time. It's not so much "getting distracted" as "not listening in the first place".
 * Charlie Brown attempting to direct his actors in A Charlie Brown Christmas, only to find out that they've headed off to dance on the stage.