It doesn't do anything yet, though. It's an idea. A good one, to be sure.

We've been looking at this kind of thing as well, but for XP we've had to settle with wallpapers. Full-screen animation can get very expensive, but it is getting relatively less so over time. Who knows what may be possible in the future?
DirectX 10-class equipment is going to be very powerful and I am sure we shall see some innovative applications from it.