My Top 5
5) Fill a trash can (standard office size, but solid and plastic) full of water. Lean it up against an inward swinging door, knock, run. Quick and dirty, but still funny. If you want to be mean, you can add a can of chicken noodle soup, but you better stay under the radar after that.
4) Had a friend who was terrified of balloons. She couldn't stand the sound of them popping. So what did we do? Filled her car with balloons so in order to drive home from school, she had to pop 'em. She actually almost started crying.
Funny side note: We ended up dating for a few months.
3) Made a copy of my friends car key without her knowing. Everyday, after she would park at school, my friend and I would sneak out and move her car to a new spot a few feet or so away. Not far enough to make her freak, but enough to confuse the hell out of her. Classic entertainment for a solid 2 months before she caught on.
2) Tie a rope from victims door knob to a door knob across the hallway. Normally pretty plain, but then flip the breakers and start running through the house screaming bloody murder. When they try to get out and can't, hilarity ensues. One friend actually tried to beat his door down with his chair.
1) My personal favorite. Had an RA (Residential Advisor) that was a douche bag. Constantly on our cases for every rule we even thought about breaking. So one night, we used up 3 rolls of duct tape and sealed him inot his own room. Watching him try to beat his way out was worth the 2 hours it took to set up.
I have a video of it somewhere, see if I can dig it up....