Washington, loosen your tie. Someday soon, there may be a conga line dancing down K Street during your lunch hour. In an attempt to restore some of the whimsy of childhood to a workaholic city, a group of Washingtonians wants to bring “adult recess and play” to the capital’s corridors of power.

“And you thought the food trucks and Occupiers were living on the wild side?” chuckled Cary Umhau, 51, a longtime District resident and founder and creative director of Spacious, an organizationthat hopes to launch “a playful revolution to help people bust out of cubicles.”

The group hopes to trick out decommissioned ice cream trucks and deploy them to cruise the city offering services such as on-the-spot hairdressing, chefs serving up cookies and milk or “recess teams” that will bring line-dancing flash mobs to downtown sidewalks. They’d be called Spacious mobiles, and you’d able to follow their routes on Twitter.

“This city is so obsessed with business and politics — you have to work 50 hours a week and then go to all the right happy hours — that we don’t prioritize recess and fun,” said Joey Katona, 23, the group’s co-founder.

Spacious and similar projects across the country constitute what stress experts call the “Play Movement,” an informal alliance of academics, therapists and human resources experts that is spreading the word about the role of playfulness in maintaining mental and physical health.

In the past seven months, there have been four national conferences on the value of play; a fifth, “The Importance of Being Playful,” will be hosted by the Minerva Foundation at the end of May at the University of California at Berkeley. A forthcoming documentary — “Seriously! The Future Depends on Play,” directed and produced by Bay Area “play consultant” Gwen Gordon — aims to illustrate how play restores health in communities around the world.

“We stop playing at our peril,” said Gordon, who’s also a member of the Association for the Study of Play, a membership organization for academics who study the salutary effects of recreation. “We think we are a playful culture, but we are really overworked. Americans on average have 13 paid vacation days per year, and most people don’t even take them. Other countries have 40. We take our weekends to play hard, but that’s really to let off steam from our play-deprived lives and just get enough energy to get back into the ring.”

The Levity Institute, based in South Portland, Maine, aims to restore “lightheartedness” to society. It advises adults to dance in grocery stores, rock out in their cars or just blow bubbles for the fun of it, said Katie West, a former life coach who runs the nonprofit.

“Certainly stress levels are very high,” said David Ballard, who directs the American Psychological Association’s Psychologically Healthy Workplace Program. The APA’s 2012 Workplace Survey found that low salaries were the top workplace source of stress along with lack of opportunity for advancement and heavy workloads.

“People are working longer hours and also don’t feel valued, which gets tied to physical and mental health and motivation — so a conga line could be a great way to get people outside, get them moving and connect humor and happiness to work, and that’s important,” he said.

That need to play is especially true in eternally multitasking Washington, where “work-life balance” means you’re scrolling through your BlackBerry during your daughter’s dance recital.

The leaders of Spacious are in many ways an unlikely ­­­pair. Umhau is a recent grandmother who’s active in her Anglican church, St. Brendan’s in the City . Katona is a nice Jewish boy who works as a paralegal and lives in a group house on U Street. They met when Umhau wrote on her blog about a scholarship Katona founded in 2006 to put a Muslim Palestinian friend through college.

“We had lunch a month later when I moved to Washington after college, and an extraordinary friendship was somehow born,” Katona said. “My friends were asking, ‘Seriously, you’re hanging out again with your grandma friend?’ ”

They created the group after she told him about her dream of “creating space for people to flourish and to have fun while deeply engaging others, especially those unlike them.” One recent example: Spacious members went grocery shopping with recent Eritrean immigrants and then everyone cooked a meal together.

No date has been set for that Spacious conga line, and the organization is still raising funds for the ice cream trucks. But Umhau and Katona are already bringing people together for events like “Be/Bring Your Own Kid Adult Recess” last week in Washington’s Meridian Hill Park. The crowd of about 65 people included doctors, State Department employees, Capitol Hill aides and tech-support workers.

“Washington’s just very high-strung,” said Ryan Lowe, 23, who moved here from Orlando and works at a litigation consulting firm. “It’s great to be at an event where I don’t have to talk about work.”

They played Twister and tug of war. They fired marshmallow guns and moonwalked. Joining in were Emily Sharpe, 32, who works for the President’s Emergency Plan for AIDS Relief, and her husband, Rob Sharpe, 34, who is a D.C. high school math teacher. They brought Hugh, their 2-month-old.

“It’s about seeking out a life that’s a little less uptight,” Rob Sharpe said.

For the meet-up’s final event, Umhau brought 72 14-ounce cans of fat-free Lucerne whipped cream and sprayed it all into pie tins. Then the group threw 201 cream pies at one another, the white goo dripping down their faces and sticking to their hair as they doubled over in laughter, licking their lips.

And, for a few minutes anyway, Washington looked a lot more relaxed.