Painting with Watercolors, Glue and Salt. Kids will love being creative and making designs with the glue. The salt creates a pretty starburst effect by soaking up paint pigments as the painting dries. And as an extra bonus: the salt sparkles!
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.