There are implants which are purely aesthetic, and then there's the Digital Tattoo Interface concept. It's a blood-powered electronic interface which is embedded under skin to mimic a tattoo, display videos, or act as a phone or computer.
As great as it seems, this concept is seriously creepy because it powers itself by converting the glucose and oxygen found in blood into electricity. But somehow getting your blood sucked by a gadget is worth it for the endless potential applications. I'd probably just end up using it to moderate comments, but what would you do first with your implant? [Core77 via Geekologie]