What a great idea. Make your own I SPY game with a VOSS water bottle. You fill it with rice and drop in little things to hide and then make a list of everything in the bottle for the kiddos to find. This is a great travel activity.
DIY Rain Stick Fill a dry empty bottle with a box of toothpicks. Add rice (uncooked) to the bottle leaving an empty space of about 1 inches at the top. Seal the lid. As you gently turn the bottle, the rice falls through the toothpicks, sounding like rain.
Indoor Activities for Kids: Homemade Lava Lamps. Vegetable oil, a about of the water bottle, then water. 10 drops of food coloring. Then take a alkaseltzer tab and break it into 4 pieces. Drop one in at a time and wait for each to dissove!
Amber BPA-Free Plastic Bottles with Black Lotion Pumps (Pack of 4)
King's Music Room: Making Swimming Noodle Ponies. This activity is 10 kinds of awesome because finally my kids will stop using these noodles as swords. Yes. sword-fighting skills are natural for preschoolers and toddlers.