Meet Marty. He’s a pumpkin that has been fitted out with a moving eyes, tongue and an expression of malevolent glee. You would probably assume that this is all driven by servos, right? Nope: Marty is driven by an old-fashioned crank mechanism, designed and built by [Ben Brandt].
He wanted to make something that could be driven by a hand crank. Of course, there is nothing stopping you from throwing a motor on the back to drive the mechanism, but [Ben] wanted the internals to be fireproof so he could light it with a candle. His mechanism, built from old bits of wire and sheet metal, is not flammable or adversely affected by heat like a motor and power supply would be. He succeeded admirably, and he has also done an excellent job of documenting the process to providing handy tips on creating a mechanical pumpkin-based monstrosity.
Those hackers down with a little electronic wet work you should start building their LED-integrated Jack-O-Lantern now. These things take a lot of time turn out.