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.
10 Ways to Repurpose Cardboard Boxes for Imaginative Play. Imaginative play is a vital part of children’s development. The humble cardboard box can make that possible. We have found 10 ways to repurpose cardboard boxes for imaginative play.