Another pinner says: Mess Free Finger Painting! What an awesome idea! Paint in a ziploc bag taped over a piece of paper. Of course we'll have to REALLY finger paint sometimes, too, since getting messy is half the fun.
Entertain your toddler's growing brain with these smart activities
How to keep a child busy for hours in the summer: DIY: Giant Ice Cube Awesomeness - filled with plastic animals, dinos, and such. And I'm sure you could put in food dye before its frozen to color it like the ice block in the photo.