There is a small know feature of Windows 7 that will allow you to feed your desktop background from an RSS feed.
What use could this be? Well desktop artists like Ryan Bliss (Digital Blasphemy) create several new images a month and you may not want to download them manually.
Ryan has a Picasa album of his free artwork for people to look through (http://picasaweb.google.com/digitalblasphemy/OfficialDigitalBlasphemyGoogleWallpapers#).
So, as a demo I have create a theme file that will be feed from that.
DigitalBlasphemy – Download this file and extract the .theme file and double click it to set it up. It will ask if you want to download all images – you should say yes!
I am going to look at creating one that uses good free 3D images and putting them together as examples!