Crash.
This game is irritatingly addictive. It's a bit reminiscent of the polar bear whacking the penguins flash games, except in true japanese style it has anime characters and combos. Unusually for this kind of game, there is no maximum possible score - get lucky and you can play it forever!
Tip: Note the 'Aerial' text on the left side of the screen - when this is blue or red you can do a combo aerial crash with your bicycle. When the game beeps, click the mouse quickly for a combo boost.
After 2 hours of playing, and an incredible sequence of luck (including 8 combos), my current highscore is 10539.90m. Beat that!
(Apologies if it's been posted before, I haven't seen it.)