I don’t know if I’d want to go under the knife for something like this if it ever truly existed someday (it doesn’t yet). Once the blades come out, my geekiness just sort of goes away, but check out this programmable dermal display via Nanogirl:

Photons emitted by these pixel bots would produce an image on the surface of the skin. This pixelbot array could be programmed to form any of many thousands of displays. Each display would be capable of two functions: (1) presenting to the user data received from the large population of medical bots that roam the user’s body; (2) conveying instructions from the user to that same large population of bots. The display could be activated or deactivated by finger tapping on the skin.

There are also a couple short movies to watch. Imagine playing Pac-Man in the palm of your hand someday. Literally.