This weekend I went to the Maker Faire. Having never been to a Maker Faire before, I described my expectations to a co-worker as it being a cross between the State Fair and the Exploratorium. It was way better than that.
Art cars, robots, and all kinds of incredible stuff. Everything was made by ordinary people who would happily tell you exactly how they made everything you saw. I also got to see Adam Savage of Mythbusters fame.
Their Cupcake CNC is a computer controlled robot that builds a 3D object layer-by-layer using molten plastic. You can buy a kit or build one from the plans freely available on their site. Their robot is based upon the incredible work of the RepRap project. The things it can build are really only limited by your imagination.