I'm a freshmen EE major, and for my engineering class project I used my new arduino to make an "Electric servo hand prosthetic with push button control", or as most people called it, Robot Hand.
It was a really simple design. I used two servos with coat hangers attached to them as the clamping mechanism, controlled with two push buttons. Theres also "glove" on the bottom that you can slip your nub into, since handless people need to attach it somehow. As simple as it all was, everyone that saw it was impressed. I don't expect to impress any of you, but just wanted to show my first project using the Arduino board. http://www.youtube.com/watch?v=blUOK6jPFq4
More of a write up here ---> http://www.blukik.com