Take a squirt gun into the rest room stall next to someone and shoot little drops over the wall every couple of seconds while pretending to pee.
740
0
Install the Blue Screen of Death screen-saver on someone's computer.
803
3
Write a message on an upside-down paper cup that alludes to something horrible being trapped under it.
Leave it on a coworker's desk or in a conference room.
1440
1
Hide all of the desktop icons on someone's computer and replace the monitor's wallpaper with a screen-shot of their desktop.
872
0
Put tape over the optical sensor of someone's mouse.
