For kids who love movies and film, you might want to introduce them to Ray Harryhausen. Harryhausen was a pioneer in fantasy films and stop-motion art. My son has been bitten by the "film producing bug" (God help me & him!) and Harryhausen is now his idol (next to Lucas and Spielberg!)
So, my son is now try his hand at stop-motion using Lego's, Bionicles and clay. We've been quite impressed with the results! It's teaching him some patience, that's for sure.