Our son is home sick so we came up with the idea of making a cardboard projector during lunch today. We used an old Jungle Oats cereal box, a toilet roll core and cling wrap for a basic lens.
We secured the cling wrap using an elastic band (hair elastic in our case) and we stuck a small piece of paper in the shape of a tree on the lens.
It is really primitive and we worked out that the LED on an iPhone projects a very clear silhouette through the projector.
Our son is working on a rocket shape to project on his cupboard door which has glow in the dark shapes and he is going to create a sort of shadow movie for his sister.