Here’s a neat trick to get a WOW background that just doesnt sit pretty but animates….use your pick of xscreensavers  as your background.
I’m running KDE 3.5 and xscreensaver 4.21.

You will need to pick some screensaver - the .desktop files are usually present in /usr/share/applnk/System/Screensavers. These are text files that describe screen saver options (your settings through configure desktop). Nevertheless, they make an excellent source for picking up screensaver commands.

To run glmatrix as your background, run

kxsrun glmatrix — -root

and presto! you should see an animated background of Matrix alphabet :)).
You can make the changes permanent by configuring advanced settings in the Desktop Configuration panel. Personally, while I like the eye candy, I hate losing the processor cycles - so I just have it as a script that I can run to impress junta :)).