What are some of your favorite office pranks? Microwaving fish in the lunch room is always a good one because it pisses everybody off. My personal favorite is to take a blank piece of paper and "fax" it to somebodies phone. Set the fax machine to make 5 attempts. Where I work, don't you dare leave your computer unlocked when you leave your desk. Somebody will add the word Jr in front of your business title in your e-mail signature line. Our Jr Senior Vice President was sending emails for 2 hours the other day before he found out. Another good one is to take a print screen of somebodies desktop, then save it as the desktop background, then hide all icons. It's hilarious to watch them click on the icons and nothing happens. What are some of your favorite work place pranks?