Real-life Quidditch is cross between dodgeball, handball
There is no golden "snitch" in the real-life version of Quidditch, so the game doesn't require a seeker, Harry Potter's position. Also, sadly, the players are not aboard broomsticks that fly.
But the rest of the game, created out of J.K. Rowling's fertile imagination, is relatively intact: as the Guardian describes, the sport is a cross between dodgeball and handball, where "Attacking 'chasers' attempt to put the 'quaffle,' or ball, past the goalkeeper whilst the opposing team's 'beaters' try to hit them with different balls called 'bludgers.'"
Hey, anything to get kids exercising, right? According to Welsh PE teacher James Vale, this game is perfect for the sedentary kids; there's no way to avoid a good bit of running around, unlike soccer or baseball, where a kid can avoid the action sought out by his more energetic and glory-lusting teammates. Because in Quidditch, you can get walloped. "When playing, standing still is not an option as doing so will certainly catch the eye of a beater and a bludger will be heading your way," says Vale.
It's brilliant, and I can hardly believe that the sport first took off in American schools, given our reputation for, oh, I don't know, banning tag on schoolyards (yes, we suck). But it's true: Muggle Quidditch originated in 2005 at Middlebury College.
Don't expect this to appear at your neighborhood middle school... ever. But do catch a Quidditch match. If for no other reason than the costumes of the audience are way better than the chest-painted fans of football.