For  those who missed the DreamScence function that existed in Windows Vista Ultimate, now you can activate this feature thanks to Kishan Bagaria from deviantART.

Just Run the Tool as an Administrator and ignore the error if you get an unhandled exception error by clicking continue. The explorer will restart and you DreamScene will be enabled.  There are 2 version, one for x64 and another one for 32-Bit Windows 7.

All you have to do next is to right click on a video, and set it as a Background. You can search for cool DreamScene Videos from here.
Download Windows 7 Dream Activator from Softpedia.