Over six months, Playwood's management worked with ChartHouse Learning of Burnsville, Minnesota, to encourage a more open and fun workplace. Cook says the office was redecorated using lively colors; employees were encouraged to use bulletin boards in public areas to post pictures of themselves doing what they loved when they weren't working.

Department heads also dreamed up events like "Jimmy Buffett days," playing the singer's music while serving key lime pie. If a department reaches a sales goal, everyone makes an afternoon run to a nearby ice-cream parlor. "The idea is that we can be serious about work but not so serious about ourselves," says Cook.

Executives, however, should be serious about humor, consultants say. Some say they won't work for a company if management doesn't agree to lead by example.

"Humor flows downhill like everything else," said Bob Mankoff, cartoon editor for the New Yorker (which, like Condé Nast Portfolio, is published by Condé Nast). An experimental psychologist by training, Mankoff conducts humor seminars at Fortune 500 companies as a sideline.

Mankoff said his approach is to ask a company's executives about what they see as problem areas—such as communication or micromanagement—before he addresses the troops. In his presentation, Mankoff draws cartoons on the subject and asks employees to write captions. (We've gathered some of Mankoff's cartoons are in a slideshow.)

"Frustration and anger create tunnel vision, but laughter is a broadening emotion that opens up creative and problem-solving channels," Mankoff says.

Patricia Clerico-Parham of Cisco Systems says Mankoff's presentation there last year helped "defuse tension in a competitive environment where there's not much downtime." His talk was "an important reminder that it's okay to have fun, and brainstorming is not about blaming," she adds.

Not all humor consultants are effective, of course. Some are frustrated comedians whose shtick would get them booed out of some clubs, according to companies that have hired them.

Take the humor consultant who wore a red rubber clown nose while speaking to a regional gathering of State Farm employees. Spokeswoman Carolyn Fujioka says he was "pretty lame and he provided no revelations."

A consultant who served up platitudes like "humor is a life-giving liquid" and "humor occurs at the speed of trust" to management trainees at McDonald's also was not well received. The company official who booked the guy angrily hung up on this reporter when asked about the experience.

Humor consultants who help employees discover how to have fun get better reviews than those who speechify or do stand-up routines.

Ann Fry, a psychotherapist turned humor consultant in New York City, said she uses role-playing exercises to help employees come up with humorous ways to deal with difficult situations. She has advised people at Shell Oil and Genzyme, among other companies.

One client, Tim Warneke, senior director of King Pharmaceuticals in Cary, North Carolina, says these sessions not only help employees learn how to "bring fun to work" but also coaches them on what is appropriate humor. "She gives feedback on what is and isn't going to fly," he says.

Of course, not everyone has the same sense of humor. Geography, gender, and status in the company may influence what people consider funny. Generally, consultants say that teasing or belittling humor is destructive, while humor that captures the absurdity or irony of situations promotes camaraderie.

"Humor will always exist as a coping mechanism," Mankoff says. "The trick for companies is to harness it so it's constructive, not subversive."