From Realtime Soft:
VideoSaver is a screen saver which plays one or more videos of your choice. Download or create your own videos, then add them to a playlist (you can create as many playlists as you like). VideoSaver supports the same video formats as Windows Media Player (except for copy-protected files).
this is good, but when you preview it with the preview option, it only plays the sound and a black screen, but when its actually playing it works, i use an avi file so i dont know about if MPEG's work or not. i recomend it highly becasue it actually works!