For his final high school project, Gabry built a robotic hand that is controlled wirelessly via XBee. The user puts on a glove and the robotic hand mimics the movements of the user.
The main components of the project are XBee, an Arduino Lilypad, flex sensors, and servomotors. In the control glove, flex sensors capture the movements and the servomotors in each finger of the robotic hand move based on the data generated by the flex sensors.
Gabry even wrote an Instructable so you can build your own. It even includes instructions on building the robotic hand and a download of the source code. Check it out here.
And take a look at this video to see the project in action.