Top 5 April Fools' Day Pranks You Can Build in the Office

On most fridges (certainly the ones in most offices), you can flip the hinges from one side to the other, allowing you, for example, to open the door on either side for corner placement. Typically, one switches the handle as well, but if you don't, the refrigerator becomes a nearly unsolvable puzzle as victims pull and pull on the handle. If no one's watching, some will even dig in their foot against a nearby counter and pull in vain directly against the hinges.

Make the switch to your office fridge right before the lunch rush, and settle in with a sandwich to watch the fun. The beauty of this prank is that once someone knows the trick, they can't wait to see someone else fall for it.

* Click to Read Detailed Instructions for This Prank at Instructables.com

One of Apple co-founder Steve Wozniak's favorite pranks was a television signal jammer. He'd "fuzz-up" a friend's broadcast connection, and, in turn, watch him perform all manner of acrobatics to "re-position" the antenna. You can have the same mischievous fun by building your own devices for blocking a remote—or turning off the TV altogether.

Remotes use an infrared LED to communicate with your TV through a series of flashes, Morse code-style (to see it in action, check out the business end of a remote in your digital camera's display). Overwhelm the set with a series of nonsensical remote flashes, or send out the manufacturer's "turn off" code to pull the same kind of prank that the Gizmodo guys got so much flack for at this year's Consumer Electronics Show.

Any of the TV-B-Gone devices (click here for a similar project from our contest) or jammers are great introductory soldering and electronics projects, with a high-fun factor for your local bar after the holiday

* Click to Read Detailed Instructions for This Prank

Got an environmentally conscious colleague whose Spring Break coincides with April Fools' Day? Sprout some seeds to turn their keyboard green! Seeds will start growing almost anywhere where there's a bit of water, so build a quick greenhouse on your own: Cover the keyboard with some wet paper towels or toilet paper, then throw it all in a large plastic bag Don't worry, people have had success dishwashing their keyboards before, so some moist paper probably won't cause any permanent damage.

This is a great prank because it's obvious that at least a week of planning went into it. Worse comes to worst? Plead innocent: "I thought you were trying to be more green!" Not enough time to germinate seeds? Try hot gluing on 1 sq. ft. of real grass turf.

* Click to Read Detailed Instructions for This Prank

Shopping carts are often protected against theft by a wheel-locking mechanism that's triggered when the vehicle leaves a store's premises. A yellow line is painted around the perimeter of say, the local market where you and a colleague might eat lunch tomorrow, and buried underneath it is a cable that emits a changing magnetic field signaling the carts to lock.

Build your own backpack-size, battery-powered yellow line to lock and unlock carts within the store, playing "red light/green light" with unwitting shoppers. That may sound a bit cruel, but the creator of this project on our site said most locked-out victims were laughing and talking to each other when stalled—and choosing a Saturday morning instead of a Monday afternoon seems to make a big difference in morale.

This is an advanced project utilizing high-current micro-controllers and signal processing, but the payoff in geek credibility is huge—and you can't even come close to buying this at a prank shop. What's more, once you've locked a friend's cart and decided you can't actually bring yourself to lock a stranger's, you'll still have a beefy H-bridge capable of controlling around a 50-volt, 30-amp-plus motor for your next build.

* Click to Read Detailed Instructions for This Prank

It's like something out of Saved by the Bell or Calvin and Hobbes: packing peanuts (or popcorn!) nearly to the ceiling of an coworker's fancy, walled-off office. But when it comes down to actually planning the prank, there are a few practical challenges—like how to fill above the door without going through the roof, or the cost of a roomful of Styrofoam.

With just a few sheets of paper, tape and a little ingenuity, you can very realistically simulate an office full of packing peanuts. While some pranks are really of the you-had-to-be-there variety, this one can be told in photos alone. The day before, set up after everyone leaves, and email an image to the victim—get 'em shaking in their boots this April Fools' Day.

* Click to Read Detailed Instructions for This Prank