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

 1548

1  

Change the coffee in the office coffee maker to decaf.

 1520

1  

Paint a bar of soap completely with clear nail polish so it won't suds up.

 802

1  

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.

 809

0  

Install the Blue Screen of Death screen-saver on someone's computer.

 882

3