How bout a little fire scarecrow!!! Take a bottle of lighter fluid and walk into someone's room. Quietly spray the lighter fluid into a pile of dirty laundry or something of that sort. Walk out of the room leaving a very discreet trail of lighter fluid leading outside, and don't forget to shut the door behind you. Light the trail and listen for the results.

Drop a load in someone's sink making sure to eat a container full of metamucil the day before.

Sack the person of your choice using a bed sheet and duct tape and display them prominently in the school trophy case or some other location.

Bring a girl to the movies and tell her you are going to grab some snacks. Get in your car and leave. I find that a remote movie theater works best for this prank. If the girl asks for a second date it was meant to be.

Conspire with your favorite black, Asian and Mexican friends and start a race riot. The results are always favorable. I think this happened once in L.A. but I might be wrong.