OoooOOo... I've just been playing with this demo of Photosynth.  It's fun and amazing on so many different levels.  The demo is a 3D reconstruction of St Mark's Square in Venice, made up of photos taken from Flikr.  The photos are arranged based on their spacial relationships, creating a virtual model that can be rotated and zoomed.  Graphics indicate where the picture was taken from and outline of other near by photos.  This demo was released almost a year ago by Microsoft Live Labs and featured at this year's TED conference. 

What is really amazing to me is how such large amounts of data can be so easily manipulated (accomplished partially by just focusing only on what is within the parameters of your screen).  For more about the technology and it's uses check out this video. (Thanks Mike!)