Treemaps give you a birds-eye coloured view of enormous #'s of details, with the ability to drill down. Some applications are finance, web statistics, e-Bay metrics, press releases, photo galleries, etc. etc.
Download an implementation of this control from Microsoft Research gallery
http://research.microsoft.com/research/downloads/
Some other MS Research goodies to look at:
Image GPS tagging.
http://wwmx.org/WebClient.aspx
http://wwmx.org/Links.aspx
