The Hy-Rel 3D is a 3D printer with four extruder heads that prints with play-doh, Sugru, plasticine, and other pasty substances. Here's a demo of the printer running four different colors of Sugru -- a great, fast-drying, dishwasher safe fix-everything putty -- to print out a (fairly low-rez) semi-sphere. The Hy-Rel was funded through a successful Kickstarter, and now sports "emulsifying extruders" that are the basis for this demo.
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.