Download the Vimeo movie (using one of the many sources on the internet, google finds this: http://clipnabber.com/ ) set as your screensaver (make a quartz composer thing, or use an app like this: http://www.apple.com/downloads/macosx/icons_screensavers/mov... ).

In terminal, run this command:

  System/Library/Frameworks/ScreenSaver.framework/Resources/ScreenSaverEngine.app/Contents/MacOS/ScreenSaverEngine -background > /dev/null 2>&1

Warning: completely untested.