In an attempt to keep our kitchen table clean for a day we decided to take crafting outside for the day. I gave her a bucket filled with water and an old paint brush, showed her how to "paint" the fence and let her go nuts. I didn't have to worry about her ruining her outfit or getting paint on anything, it was wonderful.
Then once she was done with the fence we moved on to the sidewalk, which makes a beautiful canvas for water art. When we were finished, all I had to do was dump the water out and dry our paintbrush, it was a snap.