White Goodman (BEN STILLER) is the buff and egocentric owner of the high tech and corporate Globo Gym who needs more parking space for his patrons. Thus, he decides to go after Average Joe's Gym, the small-time competitor across the street run by Peter La Fleur (VINCE VAUGHN). Goodman hires bank employee Kate Veatch (CHRISTINE TAYLOR) to investigate Peter's business and she informs the lackadaisical owner that if he doesn't come up with $50,000 in thirty days, Goodman will own and tear down his business.
Peter's resigned to that happening, but the regulars in his gym -- including scrawny nerd Owen (JOEL DAVID MOORE), pirate wannabe Steve (ALAN TUDYK), high school cheerleader wannabe Justin (JUSTIN LONG) and the somewhat effeminate Dwight (CHRIS WILLIAMS) -- don't want to take that sitting down.
Yet, only Gordon (STEPHEN ROOT) has a plan. Knowing about the winner take all Las Vegas International Dodgeball Open that just so happens to pay $50,000 to the winning team, Gordon convinces the others that it's their only hope.
Eventually recruiting Kate for their team and lucking out by having legendary dodgeball champion Patches O'Houlihan (RIP TORN) offering to be their coach, they enter the tournament. Yet, White is determined not to let Peter succeed and thus fields his own team with the likes of his burly assistant, Me'Shell Jones (JAMAL E. DUFF), and feared Eastern European champion Fran (MISSI PYLE).
With sportscaster Cotton McKnight (GARY COLE) and Pepper Brooks (JASON BATEMAN) calling the matches, Peter and his underdog team make their way through the opposing teams on their way to the big climatic showdown with White and his crew.