Office pranks are the best pranks.
Prank your coworkers by making all their copies come out with a paperclip placed on them. By replacing the paper try blanks with doctored paper that has paperclips already printed on them, your coworkers could have a mini meltdown looking for a paperclip on the copier tray that just isn't there.
This harmless prank is sure to frustrate your coworkers, and provide you with a few giggles. The best part about this prank is that it can easily be reset, ready to prank the next coworker!