Linux users: You can embed a screensaver as the destop background with two terminal commands. Tech blogger Prashanth Ellina demonstrates how you can create a "video wallpaper" by temporarily removing the nautilus desktop and replacing it with an xscreensaver. An embedded screensaver is light on memory usage, but won't play nice with Compiz Fusion.
gconftool-2 —type bool —set /apps/nautilus/preferences/show_desktop false /usr/lib/xscreensaver/glmatrix -root
Prashanth even demonstrates how to add a menu entry for turning this effect off and on. If you don't like the Matrix look, you can substitute any listed screensaver instead of "glmatrix."