I threw one in the skip a couple of months ago at work. Still worked perfectly well but we didnt use it anymore. It was a six axis Motoman robot used for gas cutting beams.
Anyway mosr robot arm are servo driven through gearboxes with brakes engaging when the motor power is off. Also encoders are used to indicate the position of the arm.
There is also a chrome plated one I think at the xscape centre at Breahead in Glasgow. I think it is called the Robocoaster and has two seats attached to it. A new idea for rollercoaster types I think.

Ian