You spin me right 'round baby, right 'round

I discovered a neat little game aptly titled "Spin the Black Circle".

The game breaks down thus: you spin the world (enclosed in the titular black circle) to move a ball towards a goal. Along the way there are spikes and fires and other nasty sorts of things you need to avoid or you die and you'll need to restart the level. The levels themselves are very well thought out and make good use of the game's physics to give the levels that perfect frustrating-but-not-impossible difficulty - and it's incredibly satisfying to complete a tricky level. Top it all off with some catchy background music, and you're likely to spend more time than you realize on this little gem.

http://www.experimentalgameplay.com/cm/g/744/spintheblackcircle.swf