we used to pull a prank in college. Take the trash can out of your room. ( about 3 gal.) All the doors in our dorm opened into the rooms. Fill the trash can with water and lean it up against the door of an unsuspecting neighbor. Knock on the door and watch them scramble out of the way of the flood. Also every dove season in college someone would kill a rattlesnake. One year a buddy of mine coiled the dead snake up on the steps leading to the second floor of our dorm. That one got some folks to steppin and fetchin. And then there are the pranks I've seen adults play. Ketchup packets under the toilet seat is a good one. And the refinery I work at keeps a bird banger pistol (sounds like a bottle rocket on steroids) to keep the starlings from roosting on us in the winter. Lets just say that if your buddy is "resting his eyes" and you shoot this contraption off he will stick to the ceiling like a scared cat.