Need a quick, easy, cheap outdoor activity?

I'm not sure why I didn't think this up on my own, but I saw this idea on parenthacks.com. It's brilliant! When you want an activity for your kiddo outside on a hot day, give him a cup of water and a paintbrush and let him "paint" the house, the driveway, the deck... whatever he fancies! It's cheap, easy, doesn't require any cleanup, and keeps him cool all at the same time!

If you wanted to do something similar inside, this would be a great idea for a chalkboard. I'm in the process of turning Ellie's new easel into a chalkboard and am thinking this is a great activity until she's actually old enough to paint responsibly. Water I can clean up off the floor. Paint, not so easily.