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

 707

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.

 719

0  

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

 778

3  

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.

 702

1  

Fill someone's hair-dryer with baby powder.

 720

1