For nearly 20 years, Cirque du Soleil has been tripping out audiences of all ages with gee-whiz acrobatics and rainbow-colored whimsy. But when Cirque’s newest show opens in Las Vegas this summer (NEWSWEEK got an exclusive peep… ah, peek), you’d best leave the kids at home. This is Cirque du Risque. But the hot, sweaty scenes of “Zumanity’’ are the least of it. Cirque’s real risk is overexposure of a different kind. The production at the New York-New York Hotel & Casino will be the third permanent Cirque show on the Vegas Strip–with a fourth scheduled to open next year at the MGM Grand Hotel and Casino across the street. By then Cirque will have, in addition to four fixed shows in Vegas and one at Disney in Orlando, Fla., five touring productions, an IMAX movie and a new, one-hour weekly variety show on the Bravo cable network. And that’s not all, folks. Cirque du Soleil is currently in talks with the MGM Mirage about a possible Cirque-themed hotel-casino at the heart of the Strip. As if that wasn’t enough, characters from the Cirque can be seen in new ads for IBM.

Is this any way to run an avant-garde circus? Guy Laliberte, Cirque’s founder, and his ragtag group of stilt-walking, juggling and fire-breathing pals started out performing for fun and meal money at street fairs in Montreal. Laliberte, 43 and a fire-eater by trade, once lived on a bench in London. Today he is sole proprietor of one of the biggest brands in entertainment since Disney. Cirque has 2,500 employees, offices in Montreal, Amsterdam and Singapore, and executives told NEWSWEEK it made $500 million in revenue last year. (A European business magazine wrote that the company’s profit margins varied between 20 and 40 percent, depending on the show, and Cirque said those figures were accurate.) Last year about 7 million people visited its touring programs and its fixed shows, “O” and “Mystere” in Vegas, and “La Nouba” at Disney World. They pay anywhere from $50 to $195 a seat for a postmodern circus that feels more like a gymnastics show performed to haunting live music. It’s all done with a slick style that makes stupid human tricks–including Chinese contortionists twisting while tiptoeing on light bulbs–look like interpretive dance.

Cirque’s new, aggressive expansion is a high-wire act itself, especially its plans for Vegas. The success of the $35 million “Mystere” show at the Treasure Island resort, which debuted in 1993, won Cirque a huge boost when it immediately displaced Siegfried & Roy as the Strip’s top sensation. The $91 million “O” at the Bellagio resort, which launched in 1998, proved that two Cirques could coexist in Vegas and be seen as distinct. Now comes the hypererotic, $50 million “Zumanity,” which sets itself apart by dropping the trapeze acts and a lot of clothing (a big debate at Cirque has been whether to use prosthetic genitals to give the illusion of frontal male nudity).

Some people on the Strip think visitors will burn out on Cirque as it grows to a fourth show and possibly its own themed resort. “Cirque du Soleil has a great track record, but it’s a question of how many this market can absorb,” says Tom Crangle, Vegas marketer for “Michael Flatley’s Lord of the Dance.” “The visitors’ choices of kinds of entertainment will be limited. You will be able to choose Cirque A, B, C, D or E.”

That may be sour grapes: “Lord of the Dance” was evicted from New York-New York last year to make way for “Zumanity.” But Ira David Sternberg, former publicist for the Tropicana Hotel and a Vegas entertainment-radio-show host agrees, “At first watch, it [Cirque’s creative takeover] looks like an oligarchy.”

MGM Mirage CEO Terry Lanni, whose resorts are home to all the Cirque shows in Vegas, isn’t worried. The 10-year-old “Mystere” still fills more than 95 percent of its 1,550 seats 10 times a week, and “O” consistently sells out its 1,800 seats. “O,” in fact, brings in more than $750,000 in profit each week. “If it comes to a point where they all begin to look like one another, that will be a problem, but there’s enough individual artistic capabilities at Cirque to avoid that,” Lanni says. “Nobody complains that there are too many Andrew Lloyd Webber musicals on Broadway.”

Laliberte says his aim is longevity–and 10 percent revenue growth a year. The potential casino-resort project for MGM Mirage fits neatly into Laliberte’s aims of establishing a chain of five-star Cirque-inspired hotels where, perhaps, trapeze artists would practice in the lobby and meals would be spoon-fed to guests by contortionist waiters. He sees them someday in Montreal, London and Tokyo, too.

Despite the Cirque explosion in Vegas, Laliberte says he’s careful not to overreach. After a Cirque appearance on the 2002 Academy Awards telecast brought a flurry of new requests for permanent shows in cities around the world, Laliberte and his top executives decided to ignore the demand and create only one new show a year for the next five years. “We could do more, we could create all of these shows right now, but the quality would suffer and it would be too much too fast,” says Cirque president Daniel Lamarre.

Laliberte insists that despite the Cirque boom, he is strictly following a business policy of slightly undersatisfying the public’s appetite. “When Enzo Ferrari was putting out a new car model, he would ask how many cars he could sell,” Laliberte explains. “If it came to, say, 250, he’d say, ‘OK, we’ll do 249.’ At every performance, I want there to be at least one person who hits his nose on the closed door of the theater because it’s sold out.” Who said running a circus was about keeping the kids smiling?