# whereis xscreensaver
xscreensaver: /usr/bin/xscreensaver /usr/libexec/xscreensaver /usr/share/xscreensaver /usr/share/man/man1/xscreensaver.1.gzIts going to be in one of the results, in my specific distribution their in /usr/libexec/xscreensaver. Once you navigate into that, simply run your screensaver with the -root switch.
./flurry -rootAnd now your desktop has been replaced by the awesome looking animated background. I would recomend you do this only if you have a medium quality video card with graphics acceleration support and use a screen saver such as glmatrix or flurry, since all the other non graphics acclerated once will eat up your CPU.

This is a screenshot of while the thing is running (glmatrix). I had to turn off my graphics acceleration so the background would be captured as well (thus the spike in CPU usage). If you have graphics accleration, CPU usage should be zero or something very small. Enjoy.
