Play Create Explore: Baby Oil Sensory Bags = baby oil, food colouring, a little bit of water, glitter, objects to find (smooth). Put in ziplock bag and duct tape for leaks and little fingers who would like to open it. ((or a heat seal bag))
Colorful Fizzy Fun: Pinner says "This kept my 2 year busy for an entire hour and my 4 year old busy for 2 hours! Drop vinegar tinted with food coloring onto a pan filled with baking soda. Sheer minutes of colorful fizzy fun!
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.