I work with some interesting folks. My immediate area, which consists of a core of a half dozen programmers, has a penchant for minor pranks and practical jokes. These generally take the form of "trashing" someone's desk when they're out of the office for more than two days. This might be anything from filling up the person's drawers with styrofoam peanuts, boobytrapping their desk so that everything falls over when they pull their chair out, or simply fixing their phone to not work. When I was gone for two weeks to get married, my co-workers covered everything on and in my desk with tin foil.
But our favorite joke has become www.YouAreDumb.com. I visited the site one day out of simple curiousity as to whether such a site existed. Its simplicity amused me, and I sent a link to a few friends around the office. Over the next week or so, I re-sent the link and we all had a chuckle to learn that we'd been inadvertently sent there again.
Since then, it has become quite the game. We've begun keeping score. You get a point if you sent someone to YouAreDumb.com, and you lose a point everytime you get sent there. Competition has been furious at times, and tactics have become quite devious. No one walks away from their machine without locking it anymore, out of fear of returning to find their home page reset to YouAreDumb.com, and everyone refuses to click on any link sent in an email, choosing rather to copy and paste the link into a browser so as not to be duped.
Tactics that have actually been used include talking the tech support guy into changing someone's home page, intentionally leaving a computer unlocked to entice someone away from their desk, writing script into the department website to send only certain logged-in users to YouAreDumb.com, (that one was mine, thanks) and logging into someone's machine remotely over the network and rewriting their bookmarks.
Work is always an adventure.