If this were anywhere else in the world, the naked man wearing only blue body paint and piercings in unmentionable places would be the freak. So would the grandmother donning a leather dominatrix outfit, the grown man wearing a giant furry chipmunk suit and the gaggle of friends painted to resemble walking zombies.

But this is Burning Man, the annual hippie-dippie experiment in radical self-expression, so perhaps nowhere in last week’s 50,000-plus-person gathering was there more anxiety about fitting in than in the two RVs that pulled up filled with what might seem the most unusual cargo for this particular gathering: nearly a dozen MBA students from Columbia University.

“I feel a little like an out-of-place tourist and that all the locals will take one look at us and say, ‘What is he doing here?’ ” said Tim Stevens, 28, of Glen Burnie, an MBA student who spent the summer working for one of the world’s largest investment banks after serving as an Army captain in Iraq. “Is it possible that we are the most boring, normal people here?”

As it turns out, no. The most radical and countercultural aspect of this famously radical and countercultural gathering is now this: Burning Man has gone mainstream.

For the first time in its 25-year history, the art festival once known as a free-spirited sex-and-drugs romp in the desert sold out all of its tickets (most costing several hundred dollars) — including to investment bankers, CEOs and government employees with security clearances who are no longer embarrassed to show up at work this week and tell their co-workers where they’ve been.

This year, the event — formed around a giant neon-covered statue of The Man and dedicated to promoting anti-commercialism — has undergone an organizational restructuring that could allow its founders to cash out as multimillionaires.

“It’s no longer considered a freak-fest in the business world. It is kind of a weirdly normal thing in a lot of circles now,” said Matt Cheney, 56, chief executive of an energy investment fund in San Francisco, who has attended for five years and is no longer surprised to run into his employees and fellow top corporate executives. “Burning Man has gone from carrying a stigma to having a cachet in the business community.”

10 principles

But the increasing popularity of Burning Man, which started Aug. 29 and ended Monday, has caused longtime Burners — as attendees are known — to wonder whether the gathering has lost its way. The culture is based on 10 principles, such as radical inclusion, unconditional gift-giving, radical self-expression and decommodification (commercial sponsorships, transactions and advertising are big no-noes). But many new participants don’t follow the principles or even know what they are.

The focus on gifting is one of the central aspects of Burning Man. Wallets are packed away, and it’s hard to walk more than a few feet through the makeshift city without someone thrusting free goods or services at you.

Interested in a free seminar? You can learn how to build an energy-efficient hexayurt at Mist’R Cools Pod, discover bondage rites of passage at the Suspend Animation Camp or hone your nonviolent communication skills with the HeeBeeGeeBee Healers. And if you’re hungry? Well, let’s just say there are more than enough vegan burritos to go around.

Except: Not all the first-time attendees (“virgins,” in Burner parlance) are participating in the gifting culture. Mark Borden, 46, a Capitol Hill resident whose Burning Man name is Booger, says the imbalance between givers and takers has been growing in the 13 years he has been attending the festival. He estimated that the number of attendees actively gifting has dropped from about 85 percent a decade ago to 60 percent this year, with a further decline likely.

“It really throws everything out of balance. You start to have these frat boys who only come here . . . because they hear this is the biggest party in the world,” said Borden, a nuclear counter-proliferation analyst for the Pentagon. (“I haven’t lost my security clearance yet,” he says, anticipating the obvious question.)

“And of course it is the biggest party in the world. But it is so much more than that. It’s hard to know what happens when not everyone participates and understands what Burning Man is all about.”

What Booger really seemed to be getting at was this: Were my fellow MBA students and I ruining Burning Man?

‘A big, fun party’

Some of us came because we had heard that Burning Man was a unique cultural phenomenon that had to be experienced. Others came to spend time with friends who were there. We all expected to have a good time but were skeptical of some of the broader ideological claims.

“It’s just a big, fun party to me. That’s about it,” said Nicholas Sidelnik, 29, a patent lawyer from New York and one of the Columbia MBA students with whom I attended school and traveled with to the festival. “I don’t really believe that this offers a vision for how to improve society. In the real world, we have scarcity and competition. It would be naive, wishful thinking to believe the whole country can be Burning Man.”

The leaders of Burning Man don’t seem too worried when asked about the influx of people who don’t necessarily believe in the 10 principles.

Larry Harvey, who originated the event in 1986 when he burned an eight-foot-tall stick figure on San Francisco’s Baker Beach, said the subversive ideas of Burning Man will eventually affect and change attendees, even if they don’t realize it during their first visit.

And Marian Goodell, one of the event’s six main organizers, said that corporate folks and skeptics are a critical part of making the gathering inclusive.

“Thank God we have that diversity,” she said. “That’s the best part of this event.”

Leah Johns, 30, and Emily Criste, 28, both newly minted MBAs about to start full-time jobs at one of the world’s largest consulting firms, said that even if they don’t share some participants’ opposition to capitalism and commercialism, they love the festival’s atmosphere of openness.

“I definitely feel like my real self here,” said Johns, who found out about Burning Man from a partner at her previous consulting firm. “There is no fixed agenda here. It allows me to live in the present, which is an incredibly freeing experience.”

Disneyland for grown-ups

It’s also an incredibly surreal experience. Call it Disneyland for adults, a giant carnival, Mad Max meets an art festival or a glimpse of Tatooine, but no description quite encapsulates the fact that standing in the middle of a barren desert, you could stumble upon nearly any scene imaginable.

A giant neon chicken carrying a few dozen passengers will drive through the dust, while nearby two women in corsets fight each other in a huge steel cage called the Thunder Dome. Giant raves with some of the best-known DJs in the world play until dawn as a 30-ton, 50-foot-tall Trojan horse that cost $80,000 to build is shot at with flaming arrows until it burns to the ground. You also might walk past a giant orgy, and you almost certainly will see people ingesting just about every type of narcotic known to man.

You can’t help but think: Is this really happening?

And then Saturday night, the giant neon-colored man burns to ashes. Johns said that, for her parents’ generation, it might seem strange to torch an effigy of The Man while working in corporate America for, effectively, The Man.

“But I think for my generation it is much more fluid,” Johns says. “It’s perfectly normal for me and my friends to identify as both countercultural and corporate.”

Like the other MBAs, she talked about wanting to return next year. But with fall semester starting for the returning students and new jobs beginning for the graduates, there would be plenty of regressions to run and spreadsheets to format before The Man could burn again.