"Vegas forced me to approach people and talk to them," he says. "I've never been able to bullshit my way into situations, and this is not a town for anyone who is quiet. But I find that people appreciate it when you mean what you say."

Cy took note of his brother's burgeoning success in 1999 and quit his gig as a machinist for an aerospace firm in Southern California. Soon he, too, was on the nightlife fast track, hosting high rollers at MGM's elite cocktail lounge, Tabú. He had a knack for making guys with $500,000 lines of credit feel important. So much so that they'd occasionally hand him $10,000 tips. Within a few years the brothers had received a course in nightclub management.

In 2001, Victor Drai poached Jesse to run the door of his eponymous after-hours club. In no time at all, Jesse was overseeing the entire operation. Four years later, Steve Wynn opened Wynn Las Vegas, which featured an ill-fated nightclub called La Bête. Drai rode in for the redo. Needing youthful partners with good connections, he roped the Twins. He gave them a piece of the profits to do the heavy lifting, and rechristened the place Tryst. In October 2005, two months before the club's unveiling, the brothers got things rolling with a huge party at La Bête to celebrate their birthday. "The music was great, the vibe was great, the place was filled with high rollers," remembers Quira Manthei, who now works at TAO. "I wanted to go to Jesse and Cy's place every night."

Steve Wynn expected the revamped place to gross $18 million in its first year. The Twins more than doubled that. "Their fuckable rating is up there," says Roman Jones, who co-owns Mansion in Miami and Privé in Vegas. "They're at the club every night. Their work ethic inspires the people they employ."

Indeed, both can be spotted bending down to pick up tiny pieces of trash that litter Tryst's carpeted staircase, and both take it upon themselves to deal with unpleasantness—everything from a dude cutting in line at Tryst to a customer lighting a blunt at Drai's.

The brothers eschew costly advertising in favor of personalized marketing. They employ a team of fast-talking, sharply dressed hosts to recruit deep-pocketed customers (bottle service accounts for 75 percent of Tryst's revenues), keep track of their preferences, and make sure they're happy at all times—whether they need a table full of girls, a birthday cake ablaze with candles, their own theme song (played right before a bunch of bottles are carried out), or table-side performances by rappers like Xzibit and Ne-Yo.

When it comes to dealing with clients, Jones says, Cy and Jesse know how to "draw the most fun and the most money out of their space. They seat one big-bottle buyer near another and try to create a competition." After the Ricky Hatton–Floyd Mayweather fight last December, Tryst instigated a "bottle war" between two high rollers, who were provided with custom-made silk boxing robes and introduced by Michael Buffer (at a cost of $5,000). The winner, a stock trader from London—nicknamed the Fireman for his habit of spritzing Dom Perignon around—ordered $160,000 worth of champagne. The runner-up, a real-estate developer from Memphis, cleared $100,000. Bottles of Dom were being carried out 50 at a time. The club grossed $1 million.