Fun with Shaving Cream
Take an "accordian" folder, and fill it with shaving cream. Put the open end under someone''s door, and jump. A nice surprise is deposited in the person''s room.
Fun with Ice Tea
This one might take several people to pull off. Take a large plastic garbage can and fill it with water. Then add a liberal amount of ice tea mix. Take the can and lean it against someones door, and knock.
In most dorms, there is enough space between the door and doorjamb and the wall to fit about four coins. Once these are in place, the occupants of the room will not be able to use the door to exit...
I see you...
With a little effort, you can actually reverse the eye-hole on the doors to rooms. Stand back and watch the show.
This one works if your dorm has showers with troughs. Take a fake severed finger and some red food coloring. Float them both down the trough, and scream. The earlier in the day, the better the result.