A UNC team has written an engine that scours Flickr for photos of a city, figures out which ones are images of the same place, analyzes them, and uses the results to build amazingly detailed 3D models -- all in less than a day, using a single PC.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.