How about finger painting or just really painting? I would have the 2 yr old paint in the bath tub or on an enormous plastic sheet. My grandchildren loved that. I found it best if I took things for them to paint instead of sheets of paper - like old chairs - you can buy these really cheap, or flower pots, etc. The bigger the items the longer you keep their interest. We even painted wooden ladders one time when I forgot to buy something. Wonderful outside activity, followed by partial washing with the hose and then bathing in the house, everyone wearing one of grandpas old shirts.Definitely something they had never done before.