Reuters Money

It’s not hard to pinpoint exactly when Tim Wiedman began to sour on the idea of April Fools’ Day pranks in the office. It was shortly after his hair had been set on fire.

Wiedman was an assistant manager at a fast-food joint at the time, and wearing one of those flimsy paper hats. His colleague Rick thought it would be a riot — and a fitting tribute to April Fools’ Day — to sneak up behind his buddy and set his cap aflame.

Rather than creating a slow burn, though, the gag made the manager’s hat go up like a bonfire on the Fourth of July. “He had to pull it off, throw it on the floor, and stamp out the flames,” remembers Wiedman, who’s now a business professor in Lincoln, Nebraska. “I’d been singed, and for several weeks, it looked like I was going bald.”

Wiedman isn’t alone is being the target of workplace mischief on April 1. According to a survey by online jobs site CareerBuilder.com, 33 percent of respondents said they’d been the victim of an office April Fools’ Day prank –- and a quarter said they’d actually done some pranking themselves.

“That’s a big number, and I was a little surprised,” says Michael Erwin, CareerBuilder’s senior career adviser. “It’s probably because people are putting up with a lot in the office these days: The staff is often leaner, and they’re expected to do more work than ever. I wouldn’t be surprised if this Friday, people try to pull something lighthearted in the office.”

Among the Harris Interactive poll’s 5,000 respondents, there were some standard gags: Gluing phones to receivers, dumping goldfish into water coolers, changing office clocks. But there were also some inspired ones, like changing a co-worker’s computer wallpaper into the screen that pops up when your entire system is about to crash. Or the hiding of a colleague’s cellphone in the ceiling tiles, so no one can locate the ring.

That last one might have been stolen from NBC’s The Office, where Jim Halpert has made office pranking into an art form with his torture of cubicle neighbor Dwight Schrute. Among Jim’s greatest hits: Sending faxes to Dwight from his future self; recruiting him for a classified CIA mission; and planting a bloody glove in his desk and convincing him he was a murderer. And, of course, the original classic of suspending his stapler in a Jell-O mold.

But it’s a fine line between having some lighthearted fun, and putting your career in actual jeopardy. “A good rule of thumb is to avoid any comments or conduct at work that you would not be comfortable saying or doing in church or court,” advises attorney Eric J. Holshouser, of Florida law firm Fowler White Boggs. “And I can tell you from experience that some jokes are a whole lot less funny when told in federal court.”

A few tips from the experts, on handling office gags the right way:

Pick on someone your own size. Pulling a brilliant prank on your boss, the one person with the authority to call security and have you booted from the premises? Not a wise idea. Similarly, picking on a poor intern could seem mean-spirited and in bad taste. Best to joke around with someone of your own rank.

Consider your target. Hopefully you’re thinking about pranking a close buddy, someone with whom you already joke on a daily basis. A more casual acquaintance, who may not share the same sense of humor? Or someone who’s already disgruntled, and might use the prank as part of their larger grudge against the company? Abort the mission. “Only do it to a person who’s going to be able to take the joke,” says Erwin.

Make sure no one gets hurt. If your prank has potential injury involved, then scratch it off the list. Not least because you’re about to give your company’s employment lawyers heart palpitations over liability issues. “It’s just common sense that you don’t want to injure anybody or stop everybody from working,” says Erwin. “And you certainly don’t want to lose your own job because of it.”

As for Tim Wiedman, the burning-hair debacle didn’t torpedo his relationship with his colleague. In fact, he was best man at his wedding a few years later. But he’s still amazed at how badly that April 1st went awry. “Since he was a known prankster, I wasn’t surprised that he pulled an April Fools’ stunt,” he says. “But I didn’t anticipate him doing something quite that dumb.”