It's like one of those "how steady is your cursor" flash games where you weave your mouse through tough obstacles. Except here, you can't see the mouse.
Update: Thanks for the many people who have favedededed... um, put this game in their favourites.
Update 2: New version now. The three main ways of cheating (holding down mouse button, pressing alt, and pressing Ctrl with the mouse settings tweaked with) have been fixed.