Since we've switched to door pranks... here's a simple one for the college dorms or even at home. Take a record album sleeve (the giant thick paper kind) and fill it with shaving cream. Slide the open end under the crack of a closed door and jump on the ablum cover filled with shaving creme. This will cover just about everything inside. It works best when no one is in the room that way you don't get chased around the dorm, and the person returns wondering how everything got covered.
