Brooklyn-based MakerBot Industries exists to make 3D printing available at affordable prices. Their devices, like Thing-O-Matic and the new Replicator, do an interesting, artsy job of that, via melted plastic and a Play-Doh aesthetic that might make hipster haters cringe, but the rest of us want to mash everything together and build more. Replicator, sold like prior products as a do-it-yourself kit and in preassembled form, works with most available 3D imaging software (and works with Mac OSX, Windows and Linux). It builds a physical 3D model based on any user-created image by feeding spools of brightly colored plastic cable (mainly acrylonitrile butadiene styrene, high density polyethelyne, and polylactic acid) through a heated extruder so that it collects in a slightly melted heap on the build platform. A robotic arm shapes the material as it cools, eventually ending up with the desired shape. Replicator is currently available in a version that prints one color at a time and a version that can print using two colors.
It ain't cheap - the single-extruder version costs $1749. But you have to admit it's kind of adorable. Here's a clip of the Replicator in action at CES, building a Rook chess piece.
(Corrected to fix inaccuracies)