What: The duck joke. Here it is told, sort of, by James Ernest, while I try to ruin it, at yesterday's w00tstock in Seattle.

Since that probably didn't help much, here it is in its entirety:
A duck walks into a bar, and asks the bartender, "Do you have any grapes?"
The bartender says, "I'm sorry, Duck. We're a bar, and so we have wine and beer and mixed drinks. But no grapes." The duck is sad, and leaves the bar.
The next night, the duck comes back into the bar and asks, "Do you have any grapes?"
The bartender says, "No, Duck, I told you last night. We don't have any grapes! And if you come back in here tomorrow night asking for grapes, I will nail your beak to the bar!" The duck hops down off the bar and runs out the door.
The next night, the bartender is waiting for the duck to come back in, and sure enough, he does. The bartender grits his teeth as the duck asks, "Do you have a hammer?"
The bartender explodes. "What? No, of course I don't have a hammer!"
So the duck says, "Do you have any grapes?"

Why: Upon hearing the duck joke from us, Adam Savage of Mythbusters wondered aloud why it worked so well. The answer, I hypothesized, is that every key word—duck, bar, grapes, hammer—is maximized for funny. (Imagine it with a chicken, a restaurant, some apples, and a mallet. See, no joke.) The joke has been optimized for the rule of three (westerners expect jokes to have three parts); when told in Japan, it is optimized for their rule of four. Everything in the duck joke has been tested and re-tested. It's the game designer's joke.

Impact: Thus and so, the duck joke has become "The Aristocrats" of the gaming industry. It is infinitely malleable, as evidenced by the German version, the Japanese version, the D&D version, the pirate version, the Office Space version (which replaces the hammer with a stapler), and dozens of others. Should the producers of The Aristocrats be reading this, we would happily direct a film for you about a joke that has an ending.

Personal Connection: I have told the duck joke more times than I can count, since I never started counting. So when geek god Wil Wheaton asked us to write a puzzle uniting the four w00tstock shows, it was a natural fit for the first of our four "juzzling" (puzzling + juggling) videos, which you can solve along with the w00tstockers as the videos get posted. And if you're near Portland, Chicago, or Minneapolis, get thee to a w00tstock!

Other Contenders: the easy-to-mangle riddle beginning "What's E.T. short for?", first related to me by ; the tragical tale of Angus the industrious Scotsman; the striking byplay between two muffins baking in an oven; three quarterbacks testify before God (note: I believe that the order of the last two may have flipped in recent years); the ultimate when playing the dozens: "Yo mama's so fat, she wore an X jacket and a helicopter landed on her back."

Update: Here is part two of the w00tstock routine, shown in Portland on May 8, and featuring the Angus joke. Also, there's part three from Chicago and part four from Minneapolis. For answers, see our Wired Decode site.