Hide all of the desktop icons on someone's computer and replace the monitor's wallpaper with a screen-shot of their desktop.

 794

0  

Put a "Please Use Other Door" sign on the entrance to your office building if it only has one entrance.

 1366

1  

Pull on a coworker is to press ctrl+print screen on their workstation, then paste it into Paint, save the pic, and set it as the desktop background. Move all of their icons to the trash. When they get back to their desk, clicking won't accomplish anything!

 1436

0  

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.

 690

0  

Place a pair of pants and shoes inside the only toilet stall in a rest room to make it appear someone is using it all day.

 674

1