Mass Effect 3 Citadel Station Dreamscene
Little app that enables Dreamscene on Windows 7 is included.
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.
Good luck and have a nice animated wallpaper.