(This is where I downloaded it from. I believe there are others, but I haven't tried them.)
This game is frustrating and hilarious. Described as a "Hard-core first-person DH bike simulator" you are thrown onto a bike and then you ride. That's it. What follows is a lot of going fast, sick jumps, flips, laughing, crashes, cursing, and frustration.
My first experience with the 'game':