Not a big fan of tattoos, me.  Don't really understand the need to accesorize in that way.  Plus, the permanancy thing.  What if you don't like it after five years?

But finally, I've come across a tattoo that I would consider.  It's not really a tattoo, it's a…

subcutaneously implanted touch-screen that operates as a cell phone display, with the potential for 3G video calls that are visible just underneath the skin.

The basis of the 2×4-inch "Digital Tattoo Interface" is a Bluetooth device made of thin, flexible silicon and silicone. It´s inserted through a small incision as a tightly rolled tube, and then it unfurls beneath the skin to align between skin and muscle. Through the same incision, two small tubes on the device are attached to an artery and a vein to allow the blood to flow to a coin-sized blood fuel cell that converts glucose and oxygen to electricity. After blood flows in from the artery to the fuel cell, it flows out again through the vein.

Still in the concept phase, and probably very expensive.  But cool nonetheless.