Heres a little thing I made for my sister as a kind of early christmas present.
It's maybe an inch - inch and a half.

The flash is made of a bunch of crappy pics I took with my compy and then I went to some pretty extreme lengths trying to script it so that when you move your mouse to the edges it spins faster.
Check out my awesome math:
(((.5*((.2*(X*X)-500)/Math.abs(.2*(X*X)-500))+.5))*(.00004*X*X*X))/2
where X is the mouse's x-coordinate relative to the center of the window.

Yeah, have an awesome new years soon!