Until TUAW reader Mark Rickert sent us a tip for the Fenêtres Volantes screensaver.
This screensaver takes your idle windows and gives them something to do - by making them fly around your display in 3D space. The effect is really slick and driven by Quartz Composer, which also means the unfortunate lack of anti-aliasing is a ball in Apple's court, not the developer's. The screensaver is fairly customizable, with controls for how many windows to use, how fast to move, whether a second display is involved, and more. Mac OS X 10.4.6 is required, as is a G4, G5 or Intel CPU at 1 Ghz or faster.
Fenêtres Volantes is donationware and available from the author's site at Objective Cocoa.