Note: This tip will only work on Windows Vista Ultimate edition.
Last Tuesday Microsoft officially released DreamScene, the first of two remaining Windows Ultimate extras. DreamScene allows you to display videos as an animated desktop background on your computer.
To install the Extras, open 'Windows Update' located under the 'Start menu' > 'All Programs'. You will see it listed under 'Widows Ultimate Extras' in the middle of the window.
For your convenience a few hundred 3D animated DreamScene desktops are available for download at dream.wincustomize.com. Also For more information on the Windows Ultimate Extras.