I have thought of many things over the last few years.
As being an F-16 crew chief I see technology in work and I wonder how easily this could be applied in medicine. Artificial limbs that move like the organic. In theory it is very easy, I have even devised a blue print for such a device.
It is not to hard to envision provided you understand the terms.

Using a bone graft you can apply a titanium plate to the bone mass and use this to graft an artificial limb on to a body. Using the latest in technology you can implant a micro chip onto the brain ( see cnn.com under technology). The chip can read brain waves to move the arm.

The arm (or leg) itself is a very simple device using either titanium or aluminum to function. Using a hydraulic pump and reservoir it would be no problem to mimic the movements of the organic body. Using a titanium bar to simulate the bone, one could mount an actuator to it. The actuator takes fluid movement and transfers it to mechanical movement. The rod end of the actuator is attached to a rotating device ( we call them bell cranks in F-16 maintenance) this is attached to another bar that acts as the other bone.
This can be used to make bends in elbows and on a smaller scale fully functional fingers and thumbs. Of course the arm or leg would need an internal power source to operate. This could be done in the way of rechargeable batteries. I think if we ever decide to apply the aerospace technology to artificial limb replacement the world would have a lot more people leading a fuller life ( not saying that people with disabilities lead a less full life, look at the author of a brief history of time, He is no doubt the smartest man alive)

I will have to talk to my wife about scanning a drawing I have to put on here, so that I may show you all my ideas.