With "anibg" you can put a XScreenSaver or a movie on your x11 desktop, you can see it as a "Windows DreamScene" pendant.
More precisely it is a frontend for the CLI application "Shantz-XWinWrap".
It works on Linux and could work on BSD and other unix based systems too, but I am not sure, because I could not test it.
It supports the languages english and german.
Ubuntu 10.04 and 10.10
Just type this in your terminal:
wget http://anibg.googlecode.com/files/anibg_v0.2.0.deb && wget http://anibg.googlecode.com/files/shantz-xwinwrap_v0.3.deb && sudo dpkg -i anibg_v0.2.0.deb shantz-xwinwrap_v0.3.deb
You need "mono", "glade-sharp-2.0", "gtk-sharp-2.0", "glib-sharp-2.0"
and "notify-sharp" to run "anibg" and "make" to compile it.
"anibg" uses "Shantz-XWinWrap" which will be delivered with this package.
To use "Shantz-XWinWrap" you need "x11", "xext"
and "xrender" and their development files to compile it.
For movie support you need "MPlayer" and "FFmpeg".
Install some "XScreenSavers", else you will not have any
Screensaver to select.
Then type these commands in your terminal:
tar -xzvf anibg_v0.2.0.tar.gz
make install # Must be executed as root