Art with kids

As summer approaches I've been thinking more about art projects that I can do with my six year old daughter, Meghan. I suppose we could get six month old Molly involved as well. 

The other day Meghan kept begging to paint with me, so I drew a Monster High character on an 8x10 canvas and let Meghan paint it how she wanted.

I've been trying to brain storm other things that Meghan could paint because I really don't want to use all my good canvases on kid crafts. Meghan already burns through a shocking amount of paper with her drawings. I saw an idea to cut up cardboard for practice canvases, so I'm going to try that out for her. Considering all the shopping I do on Amazon, I always have a steady stream of cardboard that I'm throwing away.