French foot soldiers are said to have developed the art of parkour while running, jumping and launching their bodies through the jungle canopies of Vietnam. Four decades later the acrobatic "sport" is all the rage among junior-high boys the world over. There are two things any pubescent thrill seeker requires for serious parkouring: 1) a sprawling venue with lots of light poles, utility boxes, trees and fences from which to catapult oneself; and 2) an audience young enough to appreciate said antics. That's why Six Flags is such a wicked place to parkour. The amusement park is chock-full of tweenage renegades who, once they become bored with the latest $15 million roller coaster, can impress their friends by hurling their bodies off a $15 trash can. Cowabunga, dude!