I once bet a friend to eat a fork-full of wasabi in return for paying for dinner, he had no idea what it was. The waiter overheard the conversation and stopped my friend, saying something about projectile vomiting.
One time the sushi chef played a joke on my friend and made him a roll piece using wasabi instead of rice. Man, did we laugh while he puked in their garbage can outside.
EDIT: Incidentally, if you ever have a bad cold and your nose is completely stuffed up, eat wasabi. It works like nothing else. Keep eating and sucking on wasabi until you feel it drill through the blockage.