Cool Flickr mashup from dopiaza.org:
"Flickr Set Manager allows you to automatically create new sets on Flickr based on various criteria such as interestingness, date posted and tags, or even from a random set of photographs."Link: http://www.dopiaza.org/flickr/setmgr/
If you don't know what Flickr's "interestingness" label means, here's their description.