Duct tape flapper on the driveshaft, string tied around a cup of water on top of the refridgerator and to the top of the door( Open the door, get doused..) Red food coloring inside the shower head(bloody shower), my personal favorite: If the person is a smoker, use a tiny ladyfinger. Insert it carefully into their cigarette, fuse pointed outward. DO NOT INSTALL ladyfinger too deep. About 1.5 second after lighting the 'grit, BANG!! Fly paper in the bathroom floor in the middle of the night when your buddies are super drunk( Usually they are so hammered, they just go with it for the night..) or same said fly paper on the toilet seat. Again, the really drunk ones just roll with it...