Orangeous Dailies

Wikipedia has a huge list of school pranks!

My favourites are :

1) Star Wars

The prankster claims that he has the Force. After the victim asks the prankster to show him, the prankster then licks his hand and pushes it toward the victim’s face, causing the victim to pull away.

2) Palm Cancer

This is done by informing the victim that if one’s hand is bigger than their face, they are likely to develop cancer. This invariably causes the person to position their open hand up to their face to compare the relative sizes. At that point, the perpetrator forcefully pushes the victim’s own hand into his/her face. A variant of this is claiming you can tell if someone smokes by smelling their hand, "testing" the victim and provoking a response by claiming they’re a smoker. [ i fell for this once! ]

3) Wipe-up

The prankster tells the victim to sit on the floor (Preferably tile) with his/her legs apart. He then pours some water on the floor between the victim’s legs. He gives the victim a stick, a ladle or something else. He tells him/her that if they can whack his hand with the stick before he wipes up the water with a rag, they win. Just as he is about to wipe, he grabs the victim’s ankles and drags them through the water, making it look as if they wet their pants. Especially effective in front of a large group or where a change of clothes is not easilly accessible.

The whole list here : http://en.wikipedia.org/wiki/School_pranks