Little bit of an elaborate prank, but first get your friend blind drunk, invite him to play pin the tail on the donkey. As he's about to pierce the paper donkey, hit him as hard as you can with a two by four that has a horse shoe nailed to it. While he's realing, you uncover the donkey you've kept hidden all night and place it in front of him. Once his blindfold comes off abmonish him for trying to poke your prized blue ribbon donkey with a filthy tack.
