Nexus One phone comes with LIVE wallpapers and in past we have already shared hack to install Nexus One wallpapers on Motorola Droid, method to install Live Wallpapers on the jailbroken iPhone. The video below shows live Vasvlad Wallpaper for Nokia N900 in action.
Video: Live wallpapers on Nokia N900
To install animated Live wallpapers on Nokia N900 simply invites here and install it. The result is almost what you see in the video. The use of animated backgrounds or wallpapers might affect battery life.