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.

 764

0  

Find a sleeping person, fill their hand with shaving cream and then tickle their nose.

 797

0  

Remove the shower head and place a chicken bouillon cube in it, then put the head back on.

 692

1  

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.

 748

1  

Put tape over the optical sensor of someone's mouse.

 860

1