This tutorial will show you how to run a screensaver as the desktop wallpaper in gnome and uses the xscreensaver package available from the main repository. I am using xscreensaver because the xscreensaver config dialog is much more configurable than gnome-screensaver.
Install the xscreensaver package
Open a terminal and type:
sudo apt-get install xscreensaver
Additionally, you can install the xscreensaver-data-extra package to get more screensavers and some extra tools, but they aren't necessary for this tutorial.
Normally, nautilus manages the desktop. That means nautilus is responsible for the desktop icons, wallpaper and desktop right-click menu. In order to run a screensaver as the desktop wallpaper, you need to disable nautilus' management of the desktop. This means you will lose your desktop icons, wallpaper and right-click menu. However, I have heard people say there are packages in the repos that will show desktop icons, perhaps fbdesk is one of those but I have not tested this.
Open gconf-editor, browse to /apps/nautilus/preferences and uncheck "show_desktop" key. This will disable nautilus desktop management.
Once the xscreensaver package is installed, and nautilus desktop management is disabled, run the configuration dialog with
In the "Display Modes" tab, choose a screensaver (for example I will use the Circuit screensaver) and set any other configurations you desire. I am told that the Edgy xscreensaver package may not have the circuit screensaver, but this tutorial should allow you to accomplish this with any screensaver you have. You might also go to the "Advanced" tab and set some configurations there. When you have the screensaver setup to your liking, go back to the "Display Modes" tab and click the "Settings" button in the bottom right portion of the dialog. This will show a new dialog with some settings. Click on the "Advanced" button at the bottom left to see advanced settings - including the "Command Line" command that will launch the screensaver with any configs you chose.
Running the screensaver
Enter the command from the "Command Line:" text box into a terminal using the full path to the screensaver, on Ubuntu 6.06.1 this path is /usr/lib/xscreensaver/circuit. Example command:
This starts the circuit screensaver in the root window (a.k.a. desktop). If you desire to have a screensaver running as your desktop wallpaper, you can simply run the command followed by a " &", which will run the command in the background and allow you to close the terminal without killing the screensaver. Example:
/usr/lib/xscreensaver/circuit -root &
You can also ALT+F2 and run the command from the "Run" dialog.
This method can be used for most of the screensavers, though I have not tested it with every screensaver I have.
One of the drawbacks to this is that the right-click menu and icons on the desktop will no longer be available until you re-enable the /apps/nautilus/preferences/show_desktop key. Another thing to keep in mind is cpu usage. Some screensavers can run the cpu up quite a bit and this should be considered when running a screensaver as wallpaper.