Mass Effect 3 Mars Dreamscene
Little app that enables Dreamscene on Windows 7 you can download here : [link]
Open the app choose Enable Dreamscene and right-click on unzipped clip
and choose option set as Desktop background. That's all.
If u get bored of Dreamscenes just open the app again and choose disable DS to turn it off.
DOWNLOAD IT HERE : [link]
Good luck and have a nice animated wallpaper.