I thought this was a pretty incredible accomplishment by a group of French students. They hacked a Makerbot Replicator 3d printer to turn it into a computer aided tattoo machine.

http://3dprint.com/1777/tattoo-robot...ot-3d-printer/

The students replaced the 3d printer's extruder, used for extruding plastics with a manual tattoo instrument, and then calibrated the device to perform almost flawlessly. Could the art of tattooing be on its way out as machine enter the industry?