This is just cool.

Jim Mielke's wireless blood-fueled display is a true merging of technology and body art. At the recent Greener Gadgets Design Competition, the engineer demonstrated 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.

This was an even cooler part which might get the medical industry interested as well:

Could such an invasive device have harmful biological effects? Actually, the device could offer health benefits. That´s because it also continually monitors for many blood disorders, alerting the person of a health problem.

More info here.