The Feeling Lucky? skin for the Custom iGoogle Skins gadget uses AJAX and the Flickr API to show photos of your choice as a backdrop to iGoogle.

The default Flickr group from which photos are retrieved is the HDR Panorama group but you can specify any group via the gadget's edit settings page especially since the photos in this group tend to be quite massive. A different image is used each time the page is loaded - or just hit the Feeling Lucky? button again.

Some other good group IDs to try out:
    44055355@N00 - Interestingness Top 10
    40961104@N00 - Wallpapers
    86202697@N00 - Perfect Panoramas

Here are a few random screenshots from the new skin.