Addictive game I found.

http://www.whyman.de/games/gyroball.html
Stumbled upon this link in another forum and had to share it. The basic premise is you move a ball using the arrow keys over a "3D" track, navigating it through bumps, dips, launch pads and other obstacles to its final goal without the ball hitting the edge of the track. Quite an interesting game of controlling momentum. Have a look.