To wind up is to turn the key of a toy or device that uses a clockwork motor to run. A good way to scare your sleeping dog is to wind up a mechanical hopping frog and set it loose.
You can wind up a mechanical toy (also called a wind up toy), or wind up just before you pitch a baseball. This involves a step back in the direction of second base before a forward step with the hands lifted overhead, preparing to throw the ball. Then there's the way people wind up, or end up, in some place or position: "At the end of the play, the characters wind up right where they started."