Wallsaver

Wallsaver allows you to use screensavers as wallpapers. It is a free application that allows you to have animated wallpapers on your desktop.

Wallsaver doesn't actually need to be running for it to work. You can run it once, activate it and then quite the application, and its effects will last until you re-open the app and deactivate it.

You can choose any of the screensavers that you have installed on your Mac to serve as your wallpaper. Wallsaver automatically detects and lists them under the "Preferences" tab. The app needs to be inactive for you to choose a screensaver, though. In other words, if you are running the app and have activated, you will have to deactivate to choose a different screensaver. Also, there's no way to preview the screensavers other than to activate them one by one. They are listed by name, so you can go to the Screensaver settings on your Mac and preview them there as a workaround to that problem.

All in all, the app works and does what it claims to do. I noticed that my system was considerably slower with an animated wallpaper running on the background. I don't have a slow Mac, though, so I wouldn't run this for prolonged periods of time, or when doing work.