http://www.deviantart.com/deviation/26674594/
This link will lead you to one absolutely awesome little (less than 2mb) flash game which you can easily download using 'download' button to the left of the game on the screen.
let me quote time.com for the description:
"At first glimpse, it looks like a silly scrawl. But don't let that fool you — Line Rider is becoming one of the most popular flash games on the web. Part Jackass stunt, part physics lesson, Line Rider encourages users to "draw" their own ramps, hills, and slopes with a pencil tool, then sends a virtual sledder (wearing a red scarf) along the route until he swoops, swerves and crashes. Build an elaborate enough course and you'll feel like a little kid playing in the snow again, zooming downhill, popping up in the air, wiping out on a ramp jump a la Evel Knievel."
try this out and you won't regret. cheers