Check out this post on Digital Design Blog, http://www.digitaldesignblog.com/2008/05/08/more-experiments-with-space/.
There is a pretty cool site from White Void with Z-indexed elements using flash. I guess the iPhone doesn’t support this but what a great browsing experience if you could actually touch the elements. Seems tailor-made for touch screens this one…
Duff & Puff 
it is a pretty cool use of silverlight. I got to see it at Mix08 this year. Trying to figure out what a “good” use would be other than zooming in very very close to a guitar… maybe for medical schools? human anatomy…zooming in and past organs and bones might be cool and put the technology to work…
ahhhh i reckon its going to be good for semantic search but more on that later – i am working on something – could be really cool. Have you seen Photosynth from Microsoft…?