WorldWide Telescope http://www.smh.com.au/news/web/to-infinity-and-beyond/2008/05/13/1210444410606.html For you astronomy buffs... This looks pretty cool. Unfortunately not for OSX... yet (unless you run bootcamp)
I was looking for this thread in the lounge and finally found it here. They just talked about it on G4 and reminded me about it.