Just print these and leave them out one evening along with a flashlight on the table.
Or get a book on shadow puppets.
You could discuss a little history of shadowgraphy: it faded as an art form with the advent of electric lights and tv. And if you have a budding magician in the house, they might like to know how intertwined it is with 19th century magicians.
The above engravings are from the 19th century French encyclopedia, the Nouveau Dictionnaire Encyclopédique, by Jules Trousset. Popular Mechanics magazine ran these wonderful images in a 1930 article, Fun With Shadow Puppetry for Home Entertainers:
Children who are adept with scissors might like to make paper cut-outs and perform with those, too. If they get really into it, they can project their images onto a hung white sheet for amazing effect. Shadow puppetry can be a truly gorgeous form of stop-motion animation (we discuss an app for kids to make stop-motion movies in Apps that Truly Enrich). In fact, it is very closely tied with the evolution of cinema, so if you have a budding director, try it out! Here’s another Wikipedia page with lots of elaborate Indian puppetry for more inspiration.
From the fabulous Theatre Des Ombres – check them out, too!