On September 19, teens wearing shirts with logos from companies called Tapout and Affliction mingled with millionaires and celebrities at Dallas’s American Airlines Center for UFC 103, a slate of championship fights for mixed martial arts. With over 17,000 fans on hand and an average ticket price of more than $130, UFC 103 became one of the highest-grossing events in the arena’s history, second only to a little band called the Rolling Stones.

Surprised? Don’t be. Mixed martial arts (MMA) and its leading organization, the Ultimate Fighting Championship (UFC), have created one of the fastest-growing sports in the world. Top fights regularly draw more than 10,000 people with average gate revenue of nearly $3 million. The television numbers are even more eye-popping. Charging around $50 for a typical pay-per-view purchase, the UFC generated $270 million in pay-per-view sales last year. Combined with television license fees, sponsorship, and merchandise, the UFC is expected to make more than $300 million in 2009.

Part of the excitement around MMA stems from the constant action inside “The Octagon,” the eight-sided fenced arena where UFC bouts take place. While boxing can often devolve into a dance around the ring without serious confrontation, MMA fighters combine wrestling moves, jiu-jitsu holds, kickboxing strikes, and boxing punches to subdue their opponent. Success demands more technique than brute force. An extensive set of regulations are in place both to keep the dirty stuff at bay (head butts, eye gouges, groin attacks) and to protect both combatants.

While UFC is the world’s biggest mixed martial arts organization, there are plenty of others in the United States and around the world. In fact, Dallas Mavericks owner Mark Cuban founded HDNet Fights to promote and air MMA bouts over his HDNet television channel.

MMA is even making its mark on the country’s biggest barometer of success: popular culture. The sport was parodied on a recent episode of The Simpsons, while former UFC champion Chuck Liddell competed on this season’s Dancing with the Stars. Another former titleholder, Quinton “Rampage” Jackson, is in the upcoming movie remake of The A-Team, taking on the role made famous by Mr. T.

So how did MMA go from what Senator John McCain once called “human cockfighting” to an event that draws record crowds and millions of pay-per-view buyers? Much of the credit goes to a pair of Las Vegas brothers whose family ties stretch back to Texas and the freewheeling era of mid-century Galveston.

Back then, Frank Fertitta was part of the crew that ran the Balinese Room, a legendary nightclub and dance hall that attracted some of the country’s most famous entertainers in the forties and fifties. Frank’s son, Frank Jr., grew up in that atmosphere before setting out for Las Vegas in 1960 at the age of 21. He worked his way up through the casino ranks before creating an empire of his own called Station Casinos, which was later taken over by his sons, Lorenzo and Frank III. When the brothers stepped in to buy the UFC in 2001, the sport was mired in controversy over its violent nature and was teetering on the edge of bankruptcy.

The early years of MMA were a study in a sport developing quickly and under great scrutiny. What began in 1993 as an attempt to answer the question, “Who would win in head-to-head fights between a boxer, a wrestler, and a martial arts master?,” had developed into a series of bouts with few rules and lots of blood. In that sense, it was not much different than how boxing began, except boxing had hundreds of years to develop while MMA had three before it attracted the wrong kind of attention. In 1996, McCain sent letters denouncing the sport to governors of all 50 states. Soon 36 states had barred UFC events and cable and pay-per-view providers fled.

The UFC slowly began to work with state athletic commissions to establish a unified set of rules and return the sport to some prominence, but it wasn’t until Lorenzo and Frank Fertitta III took over that the tide began to turn. As a former commissioner on the Nevada State Athletic Commission, Lorenzo was able to get the state to sanction UFC events, turning Las Vegas into UFC’s new headquarters. Although attendance and pay-per-view sales began to improve, the financial toll of running the sport continued to the point where the Fertittas were considering selling. The turnaround came when the sport was featured in its own reality show, The Ultimate Fighter.

Financed with $10 million of the Fertittas’s own money, The Ultimate Fighter debuted on Spike TV in 2005. On the show, promising MMA fighters battle for a six-figure contract with the UFC, living together and being eliminated one-by-one in tournament fights. The show became a hit and is now in its tenth edition. The most recent season premiere drew 4.1 million viewers and was the top-rated program in all of television among men 18 to 34.

“That was the catalyst,” said Marc Ratner, UFC’s vice president for regulatory affairs. “It’s given a chance for the viewing public to get to know the fighters as well as the sport. Then when people get to know some of these fighters, then they want to see their fighters compete. It’s been remarkable. Some of our biggest stars have come from there.”

One of those stars is Houston native Mike “Quick” Swick, who appeared on The Ultimate Fighter’s first season. The highly regarded welterweight fits the prototype for MMA’s modern gladiators. Nearly 70 percent of all US participants in UFC are college graduates, while 14 former Olympians and 17 former NCAA wrestling champions compete in MMA.

At 6-foot-1 and 170 pounds, lean and muscled, Swick looks like a Marine and carries himself like the boy next door. He loves his mom, posts photos of his recent wedding on his Web site, and can drop you like a bag of dirt. He’s been making enough from bouts to be able to fight full-time for the past four or five years, a level that only a few fighters have reached. The winner of the showcase bout from UFC 102, for example, pulled in a base salary of $400,000, plus a $150,000 bonus, while the loser of an undercard matchup made just $5,000. When you’re fighting just three or four times a year, the difference between winning and losing can be the difference between being a full-time fighter and teaching classes on the side.

With a 14-2 record as a pro, Swick was set to participate in UFC 103 in Dallas when he suffered a mild concussion during training. As a result, he’ll have to wait to fight again until the November 14 UFC event in Manchester, England, where he’ll take on Dan “The Outlaw” Hardy of Nottingham. The winner of that match will get a shot at the world title against one of the sport’s legends, current welterweight champion Georges “Rush” St.-Pierre.

“I try not to focus on the title shot, because without this next win, none of that is possible,” Swick said. “Getting close to a title shot and not getting close to a title shot means the same thing if you never get there.”