I have this guy at work who does pranks constantly, mostly towards his supervisor. Some of his more memorable ones:

- Placed a ballon at the wall behind the door + stuck a needle to the door in his supervisors office
- Hid a small speaker playing "happy birthday" nonstop inside the roof of his office
- Placed a box full of golf balls in our site manager's mail shelf, carved a hole in the box and waited.
- Threw an orange (yes, actual orange) at his supervisor, and hit him in the throat. Entertaining for everyone but them.