Everybody and his dog has already linked to this, which is my cue for bringing it to your attention. It's a weird little flash piece showing a bikini-clad woman falling through an endless array of spheres. She's very acrobatic, possibly as a result of having no bum. If she gets stuck, you can click and drag on her to send her on her way.
It'd be neat to convert it to a screensaver, but I don't know if that's possible.