Edit: Unfortunately, the images originally included in this post are gone, because of hosting problems in late 2009. My apologies.
A long time ago I was messing with xscreensaver and found you could paint the root window — the desktop — with a screensaver, and use it like an animated wallpaper image.
Most of those were fun for about 10 minutes, but then started to hurt my eyes … especially the 3D ones. I must be a wimp.
But there were a few I liked, and popsquares was one of them. That’s the one that throws up a series of blue squares and they fade between colors. It’s kind of neat.
I was experimenting with them on the Thinkpad today, and this time I set popsquares to use Tango colors, which gives it a more Clearlooks-esque color sequence.
Add this to your .xinitrc file for the same effect.
/usr/lib/xscreensaver/popsquares -root -bg "#3465a4" -fg "#729fcf" -ncolors 128
(That’s in Arch, by the way. But I think the xscreensavers should be in the same place in Ubuntu too. Other shades of Linux probably can do that too, maybe with a little path adjustment.) I used the ncolors flag because otherwise the colors seem to fade too fast, and it doesn’t have a retro effect.
There are other flags too; experiment with colors and shades and see what you come up with.