Thanks to one of my colleagues for showing me this, its really cool!

Daily Bing search engine images consist of awesome collection of photos from amazing nature photos to holiday sensitive events. If you  really don’t have time to change desktop wallpaper then you can use this great feature in Windows 7 to grab images via RSS feed and set them as wallpapers.

How to Set Bing Images as Daily Desktop Wallpapers
  1. Download file Bing.theme (Right Click “Save as”)
  2. Double Click the downloaded Theme File.
  3. Select Download Attachments option so that Images are downloaded automatically when Bing RSS updates.
  4. Done! You can select from the available images to show and configure Picture Position.