Better known, perhaps, for titting about on a Segway, Dean Kamen occasionally reminds us all that he's an inventor not to be underestimated. For every two-wheeled steed in Steve Wozniak's stable there's an equivalent "let's do some good" development like the IBOT balancing wheelchair. Latest on the list is a robotic prosthetic arm for members of the armed services who have lost limbs through various kinds of explosives; Dean showed the prototype in action during TED, with a video of a soldier using the arm to write.
The video is yet to appear on his site, but apparently shows the solider using it to scratch his nose, pick up a pen and perform other delicate actions. Of equal importance on a mental level is the fact that it can be covered with a perfect, mirror-image cast of the individual's other arm.