Paper Clip Daisy Chain
Take out all of your co-worker's paper clips and link them together, then put them back in the box.

Post A Fake Job Ad
Use the internet to post a fake job ad for your co-worker's current position. Use CraigsList or HotJobs or any other free online site to do this. Leave the company contact info as the response on the ad.

Full Of Nuts
Fill a co-worker's desk drawer with packing peanuts. Empty the content of the drawer out first, so you can add more peanuts.

Booby Trap Desk
Booby trap your victim's desk by attaching a piece of wire or thread that goes from the phone, wrap around the back of the desk and attached to the leg of the chair. Scoot the chair all the way in. When your victim pulls his chair out, he will knock the phone behind the desk.

Refrigerator Bandit
What could be more frustrating than a co-worker who steals your food from the fridge? Nothing! So its time for some payback. All you have to do is leave a note either on the fridge or inside. It should read something like: Stop Stealing my Food!! But if you must continue i will put a special treat in my lunch everyday, just for you! Hopefully you will enjoy it. This will cause your victim to panic and never steal again. He may think you are tampering with your own food and will avoid eating it.

No More Germs!
Post a memo in everyone's mailbox to announce a new policy to keep germs out of the office. Tell them tomorrow there will be a free keyboard cleaning session from 10am-noon in the 2nd floor meeting room. Just remind them to unhook their keyboard and stop by anytime during the session to get their keyboard cleaned. Then prior to people arriving, go and place a sign on the meeting room door that reads, "Will Retun In 15 min." Be sure to walk past there a few times during the fake seesion and see how many people were duped and are actually waiting for nobody to return in 15 min.

Fake Note
Leave a note on your victim's desk that read, "I need those PDK numbers ASAP!" Your victim will not only wonder who the note is from, but will also wonder what the heck PDK stands for.

John Tuttle
Call the receptionist and ask her to page a fake employee, who goes by the name of either John Tuttle or Allen Smythee. These are names that the movie industry uses for actors or directors that are unhappy with a movie and don't want their names attached to the project.

Water Cooler Prank
If your office has a water cooler with paper cups on the side, then this should be an easy prank. All you have to do is puncture a tiny hole with a thin sewing needle near the top of the cups. When your co-workers go to get a drink of water. they won't notice the hole until they drink it and notice the dribbling of water down their shirt.

Wooden Leg Memo
Send a memo to a new employee explaining that another employee has a wooden leg (which he doesn't, of course) but explain that he does and not to ever bring it up because it may cause turmoil in the office.