Paint a bar of soap completely with clear nail polish so it won't suds up.
 796
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.
 803
0  

Hide all of the desktop icons on someone's computer and replace the monitor's wallpaper with a screen-shot of their desktop.
 952
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.
 784
1  

Hide an alarm clock in someone's bedroom and set it for 3:00 a.m.
 833
0