Shadow play is a fun way to challenge kids and keep them busy. With the aid of a light, or even just the sun, you can make simple animal shadows on the wall, or very very complicated ones. Start here for a bit of inspiration.
Can you make a parrot on a perch?
This moose shadow is very impressive.
What about making a monster shadow. A friend can then trace around the outside to preserve the image.
Make a beautiful bird flying on the wall.
What about a challenge! Can you make the Bat signal?
What other shapes can you make?