John Paul Stapp, a retired Air Force colonel and medical researcher who once rode a rocket-powered sled at a speed faster than a .45-caliber bullet in an experiment to test the limits of human endu… ...

It's Line Rider, an online game where users draw a line and send a crude, scarf wearing, sled-rider flying down the path. (Go ahead, head to Official-Linerider.com and play a few times. We dare you.) ...

Line Rider 2 Sled-On We hit the slopes to find out how the Flash "toy" has been turned into a game. It's always dangerous taking something free and asking people to pay money for it.