Here's a little video of a toy robot that I modified. The Hex Bug toy comes with some small (watch like) batteries so I wanted to have it run on a rechargeable. I happened to get a new cordless razor from Santa so I took the rechargeable batteries from the old one and wired them on the hex bug. I also needed some well placed rubber bands to hold things together. I threw on a gum drop looking LED for that extra touch.
If you are looking for more of real robot --- watch this: