Put tape over the optical sensor of someone's mouse.
934
1
Fill someone's hair-dryer with baby powder.
818
1
Change the coffee in the office coffee maker to decaf.
1549
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.
806
1
Write a message on an upside-down paper cup that alludes to something horrible being trapped under it.
Leave it on a coworker's desk or in a conference room.
