I get really inspired by the art of children. It's so honest and unselfconscious. I love the way they deal with space, and how they figure out how to communicate visually. There is a great chart covering the phases of artistic development in children here.
I'm not the only one who is inspired by children's art. The people over at Aminals make adorable stuffed animals based on children's doodles. I think small bayer is my favorite, but they are all so gosh darn cute!