Get Your Game On These entrepreneurs are using kids' games to attract grownup dollars.

When the movie Dodgeball: A True Underdog Story hit theaters five years ago, some moviegoers reveled in the ridiculousness, reminiscing about their days playing the elementary-school sport; some were enthralled, wondering where they could participate in such a league; and others envisioned the massive potential in starting their own dodgeball league.

Adults playing sports is nothing new, but sports leagues are the latest phenomenon, as they continue to expand in cities nationwide. A 2004 report from the National Intramural-Recreational Sports Association found 75 percent of all college students participate in campus recreational sports. Fast forward to post graduation, and you have a large group of young adults who still want to get their game on.

But why is this trend picking up speed now? "It's not an emerging market, but an emerging awareness of the power that these leagues have," says Sa Dao, director of business development for Next Level Athletic Sports. He's referring to the power of the sector's demographic: Today's 18- to 34-year-olds are active, social, connected and have disposable income. "Entrepreneurs are realizing the tremendous income potential of having a database of local adult athletes," says Dao, 29. "It's a demographic with tremendous buying power."

Dao and partner Chin Kim (above, r. to l.), 38, launched their Huntington Beach, Calif.-based company last year, leveraging this buying power in affiliate relationships with companies such as Budweiser, Jack in the Box, Sharkeez and Red Bull. "You have a direct relationship with all your customers," Dao says, "and that's what businesses will pay dearly for." The pair has a soccer, dodgeball and gutterbowl database with more than 1,000 players and runs a soccer league that saw a 100 percent return rate of players this year.

Though most city leagues don't have a problem attracting adult teams, they fall short in quality, Dao says. They lack the social aspect and enthusiasm that players look for and private leagues bank on. "City leagues aren't an obstacle [for entrepreneurs], but a greater opportunity to take what already exists and make it better," he says. NLA provides its players with stats, action photos, sponsor giveaways and a sponsor bar after games.

City leagues, which are typically run on slim budgets by volunteers, can't provide a quality product to the players, says Rob Nash, a 12-year veteran in the rec-sports scene as co-founder of Extra Innings, a baseball and softball training franchise. With more entrepreneurs taking the reins, Nash says, the industry "is more organized now than it has ever been. The more organized, the easier it is for leagues like these to take on a life of their own."