People of Earth, BEHOLD! I bring you CubeStormer, your new Rubik's Cube-Solving Overlord! CubeStormer is allegedly the world's fastest "speedcubing" robot made entirely from Lego Mindstorms RCX parts. It uses a Lego webcam to scan the faces of the cube, Cube Explorer software running on a PC to solve the faces, and a whole bunch of pinchy/grabby Lego bits to manipulate the cube. My favorite part? The blinkenlights all over the edges. The blinkier the better, as far as robots are concerned.
If you're ready to be amazed and perhaps a bit confused, check out Wikipedia's entry on Speedcubing.