I've currently been working on 3rd year work!, So haven't had much to put up at the moment other than life drawings, However while collecting sound in the studio with a college. We found a toy Fire Engine, it was a wind up toy which meant it made noise when u let it move along the floor. It so happened we were after a engine sound for the milk truck in a scene.
We recorded that sound and put it with the images and it worked really well.
Never be afraid to try it may come in handy in the end.