Xkcd

"Warning: this comic occasionally contains strong language (which may be unsuitable for children), unusual humor (which may be unsuitable for adults), and advanced mathematics (which may be unsuitable for liberal-arts majors)."

xkcd is a Stick Figure Comic by Randall Munroe. It is a gag-a-day comic, and generally does not have a continuing plotline or continuity (though there are occasional short story arcs). Many of the jokes are based on math, physics, UNIX and Internet memes, as well as romance and sex.

Originally a relatively unknown set of personal sketches and doodles, it grew in popularity in 2006 when other webcomics (such as Dinosaur Comics) began linking to it. However, it was when Randall posted a "Map of the Internet", and said map was subsequently featured on Slashdot, that xkcd's popularity truly erupted. Since then, it has been among the most well-known of webcomics.

Of course, you wouldn't know that just by looking at the comic. The characters are still drawn as very basic stick figures, with no facial features other than hairstyle (which is often used to distinguish males and females). However, there are three recurring characters who can be recognized by their respective headgear:
 * "Black Hat Guy," a Jerkass Badass character with a black pork-pie hat, who in one storyline encountered a woman who out-Jerkassed him, and has now become a romantic interest.
 * A beret-clad Cloudcuckoolander, generally thought of to be an Existentialist, albeit one with a thing for pastries.
 * A dark haired woman, referred to in several comics as "Megan"; she shares many of the same interests with the nondescript Author Avatar and is commonly shown to be in a relationship with him. Was the main character of the "Choices" Series.
 * There also seems to be a recurring main character with a distinct personality (most likely the author's own), but since he looks exactly the same as all the other stick figures without hair or hats, it could be argued that he's just a stock character.

There are other recurring characters in the same social circle -- e.g. the dark-haired existential nihilist -- but most of them are less distinctive.

Has mentioned the original TV Tropes wiki. The wiki has returned the favor, taking many XKCD comics for page images (see Xkcd/Trivia for the list).

xkcd is part of the documentation for goto on the PHP website, and was mentioned as a ticket in a changelog.

Numerologists take note: adding up the numerical values of the title's letters yields a sum of 42. Coincidence? ...Yes.

Reached one thousand comics in January 2012. As the above-mentioned main character says, "Wow - just 24 to go until a big round-number milestone!"

In 2012, xkcd launched a Spin-Off blog/column called what if? in which Monroe addresses serious (but frequently off-the-wall) questions about science with a combination of surprising rigor and thorough tongue-in-cheek, along with illustrations in his trademark art style (don't forget to hover your mouse over them all).

"Guy to Guy: Wow, you suck at math. Guy to Girl: Wow, girls suck at math."
 * 20% More Awesome: Used repeatedly, including this particularly meta example involving a graph about a decline in a relationship that might be caused by graphing things.
 * Absence Makes the Heart Go Yonder: 57: Wait For Me
 * Acceptable Targets: In-universe, string theorists, liberal arts majors, 610: Objectivists (and again at 1049), 590: typographers and 114: computational linguists. Also, Velociraptors.
 * Affectionate Parody: 141: Parody Week, whose strips don't really make fun of anything and, in some cases, could actually have been used by the regular cartoonist except for the artwork. It turns into a deconstruction of parody with the author halting his Megatokyo parody because he feels sorry for the writer. The author also stops a later Penny Arcade parody because he respects the writers too much (with the respect transitioning to Ho Yay and then Slash Fic before he finishes.)
 * Aggressive Categorism: 385: How It Works.

""I hate whatever marketer first realized you could do this.""
 * AI Is a Crapshoot: 416: CTRL-C! CTRL-C! and Skynet
 * All Just a Dream: 806, "Tech Support".
 * All Love Is Unrequited: 642, "Creepy".
 * Alt Text
 * Ambiguous Syntax: Hyphen and Jacket
 * Anachronism Stew: Discussed. No one will care in the future.
 * Analogy Backfire: "And from that day on, I wore this little F key pendant everywhere I went."
 * Angrish: One comic has a father conditioning his daughter's speech centers to shut down when she's upset. Hilarity Ensues to say the least: 573, "Parental Trolling"
 * Animal Athlete Loophole: There's no rule saying a meerkat can't play rugby!
 * Applied Mathematics: It's fond of this.
 * April Fools' Day:
 * For 2010, they changed the layout so that you navigate through the comics with a text interface. If you typed in 'cat' with no arguments, you'd get There were a lot of Easter Eggs hidden in there. 'make me a sandwich'/'sudo make me a sandwich', emacs, the Konami Code... the list goes on.
 * And for 2011, all comics went 3D. Also counts as Hypocritical Humor given the April Fool's comic itself.
 * And now for 2012, the comic itself changes depending upon the web browser one views the comic with (as well as various other factors, such as location and operating system, but the web browser is the easiest to view the change with), with at least four different variations in Google Chrome, Windows Explorer, Moxilla Firefox, and Opera.
 * A list of the different variations is found here
 * Anything But That: Many of the strips revolve around Randall's fear of velociraptors.
 * Arson, Murder, and Jaywalking:
 * "There's no porn set atop storm chasing vans. No homoerotic spelling bees. No women playing electric guitar in the shower". The last one actually worked, so it probably was not so bad.
 * The future predictions for 2100 end with: "Rainforests mostly gone due to climate shifts", "All coral reefs gone" and "Gillette introduces 14 bladed razor".
 * The Alt Text for 1036 reads: "I plugged in this lamp and my dog went rigid, spoke a sentence of perfect Akkadian, and then was hurled sideways through the picture window. Even worse, it's one of those lamps where the switch is on the cord."
 * The Art of Bra Removal: It doesn't help that the mechanism to unhook a woman's bra is apparently a Rubik's Cube.
 * Asbestos-Free Cereal: The "Free" strip, featuring three brands of cereal, with one of the being asbestos-free! Provides the page image for the trope and is the Trope Namer.

"6 2 6 1 7 3 6 5 2 0 3 2"
 * Art Evolution: Compare the first 150 strips or so with the newer ones.
 * Art Shift: A few strips actually shift up in terms of quality. The author doesn't seem to have a strong inclination to keep up such things though. On occasion, Randall has created temporary UNIX-themed and 3D-versions of the comic.
 * 1021: "Business Plan" is hand-drawn, like the early strips were.
 * Art Style Dissonance: It's surprisingly smart for its limited art style.
 * Author Appeal: Randall seems to really, really like cunnilingus, going so far as to create http://cu.nniling.us/ a redirect to xkcd itself
 * Author Avatar: The plain-featured stick man. (Sometimes. It can also be just anyone without special features.) Also, this
 * Author Filibuster: Quite a few on DRM, for example here. Eventually Lampshaded here and here. This one provides a similar counterpoint, though it's not exactly a lampshade.
 * Author Phobia: Randall's alleged fear of velociraptors, Played for Laughs.
 * Author Vocabulary Calendar: Wikipedia's propensity for using specific words over and over is discussed in the strip "Malamanteau".
 * Bavarian Fire Drill: Did you know you can just buy lab coats?
 * Beware the Nice Ones: Our beret-clad Cloudcuckoolander makes some car-driving decisions.
 * Also, Stephenie Meyer. Seriously.
 * Bilingual Bonus: Assuming you speak Binary... this strip.
 * For the record, the numbers convert to:

"b a s e _ 2"
 * Alternatively, interpreted as ASCII text:

"Now and then, I announce "I know you're listening" to empty rooms. If I'm wrong, nobody knows, and if I'm right, maybe I just freaked the hell out of some secret organization."
 * Bitter Wedding Speech: Hey, you asked me to do a toast...
 * Bluff the Eavesdropper: In #525:

"I eat my body weight in food every thirty-one days. That's slightly faster than the human average. [stares off at the clouds then falls down] I'm part of the floor now."
 * Boggles the Mind: "Scrabble"; on the prevalence of dirty words you find when playing family games.
 * Bond One-Liner: Five of them, with varying degrees of awesome.
 * Book Ends: The first panel and alt-text of this strip.
 * Brains and Bondage: Chemists pick the worst safewords.
 * Brick Joke: Ongoing boomerang difficulties.
 * The Journal joke, too.
 * Does it count if they're only one comic apart?
 * Wait, isn't Etymology Man a Flying Brick? So...
 * Then there's the bobcat. The reference in Number 2 is in the Alt-Text.
 * Tetris in 724 and 888.
 * Burma-Shave: Found here.
 * Call Back: Very popular, especially in the Alt Text.
 * In "Useless", an early comic, a heart is inserted into various mathematical formulas ending in question marks. It was captioned "My normal approach is useless here." Five years later in "Probability", he wrote a strip about a terminally ill man. The Alt Text reads, "My normal approach is useless here, too."
 * Another in "Rogers St.", to "Little Bobby Tables" from "Exploits of a Mom"
 * Also, "Hell" and later, "Heaven".
 * In "A-Minus-Minus", the Black Hat Guy sells an office chair on eBay, only for the actual package to arrive at the purchaser's home a bobcat. 251 comics later in "Packages", one character sets up a script that purchases something random off eBay every day so he can continually receive packages (notice the Alt Text). The bobcat gets mentioned yet again in "Coupon Code" (Alt Text again).
 * In "Barrel - Part 1", the very first comic, a boy starts floating around in a barrel. In "Ferret", the author puts wings on a Ferret hoping he will fly. Eventually, the boy loses the barrel, and 11 comics later, in "Barrel - Part 5", is rescued by the winged ferret.
 * The man with the loud girlfriend and the elliptical dish from "Loud Sex" gets a mention in the Alt Text from "Bass".
 * In "Forks and Spoons" scientists created fork/spork/spoon hybrids, with disastrous results. Only two comics later they are mentioned again in "Making Hash Browns".
 * The mouseover in "Cat Proximity" reads "You're a kitty!" The mouseover in "Turtles" reads... well, you guess.
 * "Marshmallow Gun", where the water gun appears to be the same one from "Philosophy"
 * Black Hat Guy's past exploits are brought up in "Secretary: Part 3".
 * Many of the romance comics feature a girl named Megan with shoulder-length black hair.
 * Electric skateboards are a recurring motif.
 * So are giant hamster balls.
 * "Lemme know if you find out why she's ordering all those colored plastic balls."
 * In "Reload", the Alt Text says, "And watch out for that guy from comic #53." ("Hobby").
 * Zeppelins
 * Summer Glau:
 * As a real paladin, he fights in the name of his fair lady in "Venting".
 * He measures things by the silhouette which is always before his eyes in "Converting to Metric".
 * Oh, hey, speaking of cat captions... I IZ "IN UR REALITY"!
 * In "Circuit Diagram", the Alt Text remarks, "I just caught myself idly trying to work out what that resistor mass would actually be, and realized I had self-nerd-sniped." ("Nerd Sniping")
 * At one point Munroe produced several strips about boomerang hijinks. Then, once we've all forgotten about them, we get this.
 * Car Fu: Actually Submarine Fu: Black Hat Guy recovers his hat from his Love Interest in this strip by crashing a Russian nuclear submarine through the ice she's skating on.
 * Centipede's Dilemma: "Did you know November is Tongue Awareness Month?"
 * Children Are Innocent: Subverted hard, though partially doubly subverted when the child says "Gosh" in reaction.
 * Cloudcuckoolander:
 * Apparently, Summer Glau:

""Can anyone tell me what's wrong with this picture?" The white balance, for one. Focus is a bit too close. The chromatic aberration suggests you bought your camera because it had "the most megapixels" THE CAR IS ON FIRE!"
 * The Beret Guy can count as one as well.
 * And maybe Randall himself...
 * Coincidental Accidental Disguise: Apparently, having acne on half your face and flipping a coin is enough to fool Batman.
 * Comedic Sociopath: Black Hat Guy
 * Comically Missing the Point:

"Black Hat Guy: I plead the third. Congresswoman: You mean the fifth. Black Hat Guy: No, the third. Congresswoman: ...You refuse to quarter troops in your house? Black Hat Guy: I have few principles, but I stick to them."
 * Continuity Nod: See Call Back.
 * Convection, Schmonvection: Would someone please inform these kids of this trope. (It's not completely their fault; they're re-enacting the plot of Volcano.)
 * Cool Shades: A derivative of this trope (with a reference to the CSI Quip to Black), as seen here.
 * Crazy Prepared:
 * Can go wrong.
 * Also found here.
 * Creator Breakdown: In 2010 Monroe discovered that his fiancee has cancer. Coincidentally, quite a few comics he wrote afterward touch on the subject.
 * Creepypasta: Parodied here.
 * Cuteness Proximity: Shown in the strip "Cat Proximity", which is the Trope Namer as well.
 * Darker and Edgier : Played with in-universe by Harriet the Spy
 * Date My Avatar: This strip demonstrates how the internet makes you appear smarter.
 * Deconstruction:
 * Fun seventy years, indeed.
 * When we said to make it more realistic, we meant the graphics.
 * Defictionalization - wetriffs.com, mentioned in a spoof of Rule 34, is now a real thing. Granted, not terribly detailed. And no, we're not linking to it.
 * A Degree in Useless: According to the Alt Text here, anthropology.
 * Also, literary criticism.
 * And now, apparently, all of them.
 * Department of Redundancy Department: The Tautology Club is about redundancy because redundancy is what the Tautology Club is all about.
 * Description Cut: Surely Nathan Fillion has better things to do these days than pretend to be Mal Reynolds. Meanwhile, wearing a brown coat, "Name's Captain Reynolds, ma'am." *ahem* "Name's Captain Reynolds, ma'am." Made even funnier by a certain episode of Castle
 * Determinator: "He just reconnected the cables we cut, muttering something about "uptime".
 * Devil's Advocate: Invoked but not used here. The trope itself is used without Name Drop in the Wright Brothers example.
 * Did You Actually Believe?
 * Did You Just Scam Cthulhu?: Mephistopheles encounters the E.U.L.A
 * Disproportionate Retribution: Lots. Here're three examples.
 * Distracted From Death: In this strip a guy is so worried about this happening that he forces in sweet last words even when his love interest is just going to the grocery store.
 * Dogged Nice Guy: ... or, we could be friends! Especially notable in how unsympathetic the whole nice guy situation is played, with xkcd generally favoring rather sappy and simple romance comics.
 * Don't Explain the Joke: The comic frequently violates this rule. In many cases, the punchline occurs in the second-to-last panel, only to have a final panel that then explains it. Other times the punchline is in the last panel... but there's a final sentence that then explains the joke. On the rare occasion neither are done, you can probably check the Alt Text and find it explained there.
 * Don't Try This At Home: See the Alt Text for Wings. Subverted in a blog post: "But remember, I am not advocating doing anything dangerous unless it’s really cool."
 * Dream Apocalypse: "Please don't wake up. I don't want to die."
 * Droste Image: This.
 * Drunken Master: In the form of Ballmer's Peak.
 * Dying Alone
 * Eagle Land/GlobalIgnorance: Deconstructed in this strip.
 * Eldritch Abomination: This is why you shouldn't awaken the sheeple.
 * Elemental Powers: Elements
 * Elevator Gag: Floor 5: Zeppelin!
 * Even Evil Has Loved Ones: Black Hat Guy and his girlfriend
 * Even Evil Has Standards: While going over Black Hat Guy's (extensive) criminal record...

"Black Hat Guy: Let's make a deal. You stop trying to tell me where, when, and how I play my movies and music, and I won't crush your homes under my inexorably advancing wall of ice."
 * Face Palm: Here is an example (last panel).
 * Failure Is the Only Option: This flow chart explains how to write good code, or possibly not.
 * False Dichotomy: "Charity" discusses this.
 * Fantasy Twist: This strip takes it to a very weird place.
 * Far Side Island: If this strip is to be trusted, they're not half as boring as they're stereotyped.
 * Feghoot
 * 90 years worth of predictions for the future... only to end in an extremely lame meme.
 * Lampshaded, then subverted here.
 * Fetish Retardant: In-universe, the Power Rangers theme is this.
 * Filler Strip: Parodied.
 * Flat World: Here, in a reference to Flatland. (Bonus points for the Alt Text pointing out what a stick figure would look like according to the book.)
 * Flock of Wolves: What are the odds of five Ayn Rand fans being on the same train together?
 * Geeky Turn On: Frequent, though with occasional unfortunate Manic Pixie Dream Girl overtones.
 * Genre Blind: Genre blindness in horror movies is made fun of in this strip
 * Genre Savvy: "The outbreak started with patient zero... and ended with patient zero five minutes later."
 * "Gift of the Magi" Plot: At least the result was the same.
 * Girl in the Tower: This girl wants to be a lighthouse keeper because she gets to be the girl in the tower, only she's the one saving people.
 * Girl-On-Girl Is Hot: Go go Gadget two lesbians doing it.
 * Glasses Pull: Done by both Rick Astley and Isaac Newton for particularly dreadful puns.
 * A God Am I:
 * 676: The result of realizing how much computing power is available to the average person.
 * 505: Speculating that a deity might be creating the universe out of boredom.
 * Godwin's Law: Referenced and parodied in this strip. Also, the suggested a screen consisting entirely of Hitler's face with flashing eyes would be preferable to Vista.
 * Going Mobile: There is a mobile version of the site, even with a button to click to show the Alt Text.
 * Golden Mean Fallacy: Played for laughs here. The Alt Text explicitly states: "I believe the truth always lies halfway between the most extreme claims."
 * A Good Name for a Rock Band: Or for a Tumblr.
 * Inverted in the Alt Text: "Dot Tumblr Dot Com" would not make A Good Name for a Rock Band, due to potential confusion about its website.
 * Gets skewered here, as well.
 * Gratuitous Iambic Pentameter: Strip 79, "Iambic Pentameter".
 * Guest Strip: A week full of them, by the authors of Questionable Content, Buttercup Festival, Overcompensating, Saturday Morning Breakfast Cereal, and FoxTrot. Yes, Bill Amend did a guest strip.
 * Hard on Soft Science: With some frequency. It also appears in the warning at the bottom of each page. Homeopathy is a soft target, but perhaps Some Anvils Need to Be Dropped.
 * Hitler's Time Travel Exemption Act: Black Hat Guy uses a one-time-only time machine to go back and kill Hitler, at his friend's insistence. Only he did it in 1945, in the bunker, which is when and where Hitler actually died.
 * Hoist by His Own Petard: "I just caught myself idly trying to work out what that resistor mass would actually be, and realized I had self-nerd-sniped." In-universe, the strip just before that one.
 * Homage
 * I'd Tell You, But Then I'd Have To Kill You: Well, kill you even sooner.
 * Incredibly Lame Pun:
 * Rather blatantly in strips 282, 594, and 626.
 * "I'm sorry if I hurt anthropology-major feelings with Friday's alt-text. I meant it as a friendly jibe at a cool field. I ... anthropologize."
 * This one has two, one as the punchline and one in the Alt Text.
 * 460: Palaeontology.
 * A comic the author drew as a part of a game features Richard Wagner chasing a guy on his "Ring Cycle". He commented: "Why did I draw this?"
 * Complex Conjugate. Oh my Eris...
 * Not just your significant other. Your "statistically significant" other.
 * This strip's Alt Text.
 * 345: You'd make a wonderful dread pirate, Roberts.
 * This. A lampshade is hung in the alt text.
 * He thinks he drew this one to get back at people going through his stuff.
 * They did this one on purpose.
 * The alt text here, accompanied by a Glasses Pull.
 * Instant AI, Just Add Water: Very easy on Python! (as usual, Alt Text explains how)
 * Internet Backlash: Many people were angry at #631, as well as the alt-text in #764.
 * In the Style Of: Many of his parodies fit this trope a little closer.
 * Inverted Trope: Well, if it were a trope...
 * It Meant Something to Me: The spambot.
 * It Was His Sled: parodied.
 * I Want My Jetpack: Replace "jetpack" with "flying car" and the trope name's quoted word-for-word.
 * I Will Find You: Find You
 * Jerkass: Black Hat Guy.
 * Jerk with a Heart of Gold: "No One Must Know".
 * Jumping the Shark: Played with in-universe in this strip's Alt Text.
 * Know Your Vines: Relationship after camping trip: strained.
 * Leaning on the Fourth Wall: The punchline of #1054 depends entirely on you reading the speech bubbles instead of imagining them as spoken dialogue.
 * L Is for Dyslexia: Double subverted in this strip. And then subverted a third time in the Alt Text.
 * Logic Bomb: Used several times, but this one's for the audience.
 * Logical Fallacies:
 * An intentional example in 'Extrapolation'
 * Lampshaded here, in the "Principle of Explosion" comic.
 * Loud of War: Several strips have featured inventive audio revenge on loud car stereos and neighbours who are loud in bed.
 * LOLcats: "What are you doing?!" "Gluing captions to your cats."
 * Love Allegory: Katamari.
 * Also, "Our love is like a Brontosaurus".
 * Love You and Everybody: I love the whole world.
 * Major-General Song: "Every Major's Terrible", which is about choosing a course and how the person can't/won't/doesn't want to do any of them. Someone sang the whole comic (with accompaniment) here.
 * Note that the video was released within hours of the comic. Say what you will about XKCD's fandom, but damn.
 * Manic Pixie Dream Girl: the female character.
 * On the other hand, most characters in the strip have a strong devotion to making life a little weirder from the start, including Black Hat Guy.
 * The appeal of this trope is parodied in comic 122: "I didn't actually mean be different. I just want silly and entertaining on command now and then."
 * But played completely straight here.
 * Measuring the Marigolds: Subverted in "Beauty". Yes, scientists find beauty and wonder in their work. It's just not always what everyone else thinks of as beautiful.
 * Michael Bay: Knows the worst-case scenario.
 * Mighty Glacier: Used literally in "Digital Rights Management".

"We did not invent the algorithm. The algorithm consistently finds Jesus. The algorithm killed Jeeves. . The algorithm is Banned in China. The algorithm is from Jersey. The algorithm constantly finds Jesus. This is not the algorithm. This is close.
 * Milestone Celebration: Only 24 Comics left till the *real* milestone!
 * Ironically averted when "the *real* milestone" came.
 * Mind Screw:
 * Here. Just so you understand how weird this is, the guy on the right is talking to the past, and it's talking back.
 * This strip starts out fairly normal. Then the whole world falls apart all of a sudden.
 * The small print about "the algorithm" on the home page might also qualify as either an example or a parody:

The story behind that is as follows: In 2007, some billboards popped up in New York with those sentences on them, as part of an apparent viral marketing campaign by ask.com. However, they apparently didn't finish it; the phrases didn't return anything relevant on Google. Randall decided to exploit this by having the many bloggers in his fanbase post the sentences as links to xkcd.com. He added them to the site itself so that the effort wouldn't be misinterpreted as an attempted Googlebomb. It worked; if you Google the phrases, the top results are all references to xkcd."

"Alt Text: Guest comic by Bill Amend of FoxTrot, an inspiration to all us nerdy-physics-majors-turned-cartoonists, of which there are an oddly large number."
 * Mood Whiplash: Too many to fully enumerate. Some examples:
 * Here.
 * "Dark Flow" segues from a Your Mom gag to something rather heartbreaking.
 * Mundane Made Awesome: In the xkcd-Verse, computer science is revered as if it were a martial art. The 1337 story arc is a good example.
 * Mundane Utility:
 * Frequently, including lasers to zap squirrels.
 * Also, using the LHC to cause cancer in helicopters.
 * Mundane Wish: Done in this strip.
 * Nameless Narrative: Most of the names of recurring characters were never clearly stated.
 * Averted with 'Megan'
 * The alt text of the Actuarial strip names the Black Hat Guy as "Hat guy."
 * The Author Avatar may be named Rob.
 * Never Bareheaded: Black Hat Guy.
 * Except the one time his hat was stolen.
 * Nightmare Fuel: Velociraptors, In-Universe.
 * Ninja Pirate Zombie Robot:
 * This strip.
 * Examined further in this one.
 * Noodle Implements: Invoked here, to the dismay of the characters.
 * Noodle Incident:
 * Whatever the rest of "Comic fragment" was.
 * Also, he somehow managed to go from upgrading a computer to being stranded out in the middle of the ocean surrounded by sharks.
 * Then we have #521. Start with trying to one-up some christmas light displays on Youtube. End up fighting raptors with lightsabers, Bill Gates killing Santa, and finally cutting down the Yggdrasil as a Christmas tree.
 * And however he lost his genetics, rocketry, and stripping licenses in one go.
 * Office Sports: What programmers get up to while their code's compiling.
 * Off the Chart: This comic describing The Star Wars Holiday Special.
 * Ontological Mystery: #505 starts with this, and then puts another layer on top.
 * Organ Theft: Inverted in 914. His ice is stolen... and he wakes up in a bathtub full of kidneys, rather than the other way 'round.
 * Overly Long Gag:
 * On TV Tropes
 * Significant, which even combines this with Overly Pre-Prepared Gag.
 * Overly Narrow Superlative: "I love you most out of all the girls in all the world who love me back." May double as a False Reassurance.
 * And subverted in Bill Amend's guest strip:

"The point is that there are too many stars. It's been freaking me out."
 * Overly Pre-Prepared Gag: Just shy of a hundred years of Googled predictions for the future, until you get to 2101.
 * Parking Payback: "Police reported three dozen cheerful bystanders, yet no one claims to have seen who did it."
 * Parting Words Regret: Discussed in Leaving.
 * Person with the Clothing: Black Hat Guy.
 * Pizza Boy Special Delivery: Subverted.
 * Pluto Is Expendable: "It's been two years. I thought those wounds had healed. But I stand by what I said. Pluto never should have been a planet."
 * Poe's Law: Referenced here.
 * Poor Communication Kills: Demonstrated here.
 * Porn Names: Discussed here.
 * Power Perversion Potential: 3D printers.
 * Premature Aggravation: 439, "Thinking Ahead". "Did he just go crazy and jump out the window?"
 * The Presents Were Never From Santa: He's an agent for the "forces working beneath the chaos of life"...or maybe not.
 * Public Secret Message: This strip makes fun of the public messages in Redwall.
 * Quip to Black: Here. (The CSI meme version.)
 * Really Gets Around: Touched on here.
 * "The Reason You Suck" Speech: Given by the target of a pickup artist in this strip.
 * Record Needle Scratch: Apparently a good name for your daughter.
 * Red Pill, Blue Pill: parodied.
 * Reference Overdosed
 * Remix Comic: the forum-produced Making XKCD Slightly Worse. Notable is the fact that the spin-off comic has more than three times the number of strips than the original.
 * Repeating So the Audience Can Hear: This one. Lampshaded by the Alt Text.
 * Reverse Psychology: Black Hat Guy warns vandals not to mess with his jack-o-lantern.
 * Rickroll:
 * Mentioned several times. This strip actually includes the opening score, making for what has to be the most subtle Rickroll ever (unless you can read music).
 * They actually rickrolled Rick Astley
 * Subverted in this strip - they hire Rick Astley to show up at a party and not sing. Complete with Glasses Pull and Quip to Black.
 * "They kept Rickrolling me! It was only fair."
 * Rule Number One: The first rule of the tautology club is first rule of the tautology club.
 * Rule 34: If there are no actual Strunk/White erotic fanfictions out there now, there probably will be as a direct result of this comic.
 * Discussed by name.
 * Running Gag: Cory Doctorow blogging in a hot air balloon from the blogosphere.
 * Also Raptors
 * Sarcasm Mode: "Try an Internet petition drive - those totally work."
 * Science Is Wrong: "No one told you because you're cute when you get into something."
 * Selfcest: You'd think this is going somewhere dramatic, but no.
 * Self-Deprecation: One way to interpret this strip.
 * Self-Imposed Challenge: A rare non-video game example: This strip inspired an actual Flash implementation of the game. It's pretty unplayable (that's kind of the point) with the usual Tetris goals, but a MeFite pointed out the game is actually interesting and reasonably challenging if you try to end the game with as few pieces as you can.
 * Sesquipedalian Loquaciousness: Wikipedia's propensity for this is discussed in the strip "Malamanteau".
 * Silent Scenery Panel: The occasional landscape drawings.
 * Shaped Like Itself: The basis of 688. And 703.
 * Schmuck Bait: "Jeffrey is famous as the picture on the Wikipedia article on 'Necrosis'"
 * Shout-Out:
 * Many, but of particular note is this one. It gets worse. Click the comic itself.
 * Earlier than that, we have "In Popular Culture". It's very subtle, but take a look at the works listed as examples. Any of them look familiar?
 * Calvin and Hobbes say Hi. And again (this one also contains Shout Outs to Rocky and Bullwinkle and The Lord of the Rings).
 * In the first "1337" comic, one character poses the question, "How does she type with oven mitts on?" This is a reference to a frequently asked question on Homestar Runner's Strong Bad emails, and possibly also a reference to his "training gloves" in the site's "In Search of the Yello Dello" toon.
 * The Alt Text on this one is a reference to an obscure detail in The Voyage of the Dawn Treader.
 * Hannelore's twitter account is seen during this strip about swine flu.
 * In the same one, it also has someone asking how long it'll take the flu to reach Madagascar.
 * "Craigslist Apartments" has a few notable addresses, including one house on scenic Ash Tree Lane.
 * Strip Games. See the Alt Text? Right.
 * Black Hat is based on Aram from Men in Hats in many ways
 * Hofstadter and his recursiveness.
 * Jason Fox makes a cameo appearance in this strip.
 * The Alt Text of this strip is "We have met the enemy and he is us".
 * Gravity Wells has a couple of things in Titan going "weeoooeeooo".
 * Slow-Loading Internet Image: Discussed in this comic.
 * Smart People Play Chess: On roller coasters, no less.
 * So Bad Its Horrible: Conversed here.
 * Something Person: Etymology-man!
 * Sophisticated As Hell:
 * Strip 36
 * And this one
 * This happens a lot. Check this strip.
 * Space Elevator: After countless engineers / spend trillions over fifty years, / a modern Babel disappears / because some fuck brought pruning shears.
 * Space Whale Aesop: This is what happens when you use GOTO.
 * Special Edition Title: On October 26, 2009, the site was temporarily redesigned in a Retraux early 90's style in dubious honor of the end of Geocities. Complete with broken HTML!
 * Spin the Earth Backwards: Sort of.
 * Spy Speak: Parodied.
 * Stalker with a Crush / Dogged Nice Guy: Once again, Strip 513. You'll understand.
 * The Stars Are Going Out: Invoked Trope in this strip.

"Chomskyists, generative linguists, and Ryan North, your days are numbered."
 * Stealth Pun:
 * This strip.
 * In this strip, where an audience member lampshades its use.
 * Step Three: Profit: Mentioned in the Alt Text here.
 * Stick Figure Comic
 * "Stop Having Fun!" Guys: Trope Namer. This strip shows a guy deriding a few people playing Rock Band, telling them it doesn't make them cool ... even though they're having fun.
 * Stuffed Into the Fridge: The combined volume of Summer Glau, Dennis Kucinich and Ron Paul is less than the volume of the fridge! Here.
 * Swallowed a Fly: This strip, referencing a similar example in Serenity.
 * Swivel Chair Antics: Graphed.
 * Take That:
 * As required for any "real" computer user, the strip hates Windows, especially Vista.
 * Computational linguists are also targeted occasionally. Because fuck computational linguistics. In the Alt Text:

""Are the raptors contained?" "Sure. Unless they figure out how to build lightsabers.""
 * While all those are often partially tongue in cheek, DRM gets searing loads of venom.
 * Randall also makes his views on string theory fairly clear. Brains vs string theorists is a very Old Pun.
 * Fuck grapefruit. Fuck coconuts.
 * This for people who endlessly parrot Python.
 * Fuck literary criticism, philosophy, anthropology, psychology... basically, any field that isn't physics, mathematics, or computer science.
 * He has also declared war on chemists, though that's more a grudging rivalry than a belittlement.
 * With some exceptions, like the one against homeopathy, the Take Thats are usually intended to be in jest. Occasionally the comic doesn't make this entirely clear; notably, the one against anthropology majors was so widely seen as a serious insult to the field that the author later issued an apology for it, as noted above under Incredibly Lame Pun.
 * Fuck the cosine
 * Console Lines. Xbox / Playstation fanboys take care.
 * Fuck Cancer.
 * "Suckville is considered by the Census Bureau to be part of the Detroit Metropolitan statistical area, despite not being located anywhere near Detroit
 * Another Alt Text one: "I've been trying for a couple of years now, but I haven't been able to come up with a name dumber than 'Renesmee'."
 * Tempting Fate: A couple times in this strip.

""Fine, walk away. I'm gonna go cry into a pint of Ben&Jerry's Brownie Batter(tm) ice cream [link], then take out my frustration on a variety of great flash games from PopCap Games(r) [link].""
 * Terrible Ticking: Unn-tss, unn-tss, unn-tss...
 * The Calls Are Coming From Inside the House: Spoofed.
 * There Are No Girls on the Internet: This strip addresses the author's theories about the reason for that.
 * This Is for Emphasis, Bitch: Science. It works, bitches.
 * This Is Sparta:
 * FUCK. THAT. SHIT.
 * MISSION. FUCKING. ACCOMPLISHED.
 * To Be Lawful or Good: He chooses lawful.
 * Tradesnark: In this comic's alt text after the spambot is found out:

"Person: Try the physics lab next door. Zombie Feynman: I said BRAINS. All they've got are string theorists."
 * Truth in Television: The "Get out of my head Randall!" meme where many of the comics are applicable to the everyday lives of the readers.
 * Tropes Will Ruin Your Life: Possibly the first actual work to use this?
 * Twice Shy: This strip. And again.
 * Un Installment: 404
 * Unsound Effect:
 * Draw. Make make. Scoop. Pour. Tie. Rumble. Boom. Crack. Fuse. Follow. Detach. Open. Remove. Admire. Examine. Grind. Set. Approve. Give.
 * Up to Eleven: The basis of 670.
 * Unholy Matrimony: Hat Guy acquired a girlfirend in a mini-arc, who shares similar interests and is more than a match for him. She comes up again, but slightly more rarely than he does.
 * Vanity License Plate: The tendency of such plates to be owned by pretentious rich jerks is parodied, and Black Hat Guy claims another victim.
 * Victorious Childhood Friend: Deconstructed here.
 * Viewers Are Geniuses: One of the biggest practitioners. The strip often bases comics on obscure math, physics, or computer jokes. This has gotten less common over time, and the forums are very useful. You may need to be knowledgeable in several possibly obscure or complicated fields to completely get some of the earlier ones. For example, computer programing, meteorology, cosmic rays, and tao philosophy. Really.
 * Viewers are Morons: This directly goes against the above assertion, sometimes twining the two. It's also connected to the above Don't Explain the Joke. While many of the jokes in the strip are aimed towards those in specialized fields or hobbies, Randall has a tendency to explain these references and jokes within the comic in such ways that often kill it.
 * Visible Silence: E.g. the end of this strip
 * We All Live in America: The old World According To Americans "map of ignorance/prejudice" gag is subverted when the Americans asked turn out to be "unexpectedly good at geography" and also aware of the holes in their knowledge.
 * We Are as Mayflies: To the time vultures, at any rate.
 * Weird Currency: Here.
 * Wham! Episode: Randall reveals that due to illness in the family, the next few weeks are going to be filler. Normal updates resume. Then five months later, he gives us a Tear Jerker with a heart-breaking Ironic Echo.
 * What Is This Thing You Call Love?: My normal approach is useless here.
 * What Measure Is a Mook?: Done via FPS mod.
 * When All You Have Is a Hammer: Parodied.
 * White Knighting: Occasionally the kind is accused of engaging in this kind of behavior, something directly parodied by Chansawsuit here.
 * Why Don't You Just Shoot Him?: This comic points this out, specifically with regards to zombie movies that start in labs.
 * Why We Can't Have Nice Things: You could argue that it's subverted in the Alt-text... but not by much.
 * Wiki Vandal: Wikipedia articles are frequently defaced whenever a relevant topic is mentioned, as this blog documents.
 * Wiki Walk:
 * This shows the danger of falling into these.
 * This comic describes the trope perfectly.
 * Women Are Wiser: The women usually play the more sensible part in the comic.
 * Word Puree Title: Explained here.
 * X Days Since...: 38 days since someone reset this sign.
 * X Meets Y: Dirty Harry meets Rain Man, if only for one strip.
 * Ye Olde Butcherede Englishe: One of the strips is the trope page. Also this.
 * Your Mom: Played with frequently. The trope is also used. Subverted here. Is in the Alt Text here and here.
 * Mrs. Roberts defaces websites of people who tell these jokes to her daughter.
 * Another one, and still another
 * She apparently has a deeper gravity well than Saturn.
 * You Answered Your Own Question: Happens here
 * Your Brain Won't Be Much of a Meal: When Zombie Feynman wants brains after explaining how Myth Busters are true science:


 * Zeppelins from Another World