My very artsy sister-in-law drew a lot on our basement walls 6 years ago when she was going through stage 4 breast cancer. I think it was very therapeutic for her. She created centers for the kids, and made fun wall signage with chalk. She died 5 years ago. We still have a memory of her everytime we wander down to the basement.
So, grab your kids some chalk, and let them start drawing. The chalk can always be erased, but the memories will last forever.
Drawing is still basically the same as it has been since prehistoric times. It brings together man and the world. It lives through magic.