18 FREE & GENUIS BACKYARD DIY'S: Transform your backyard play space from ordinary to extraordinary with these easy, inexpensive and awesome play features! Your kids will never be bored again! They may never want to come inside again either! - Happy Hooligans
Another Pinner said: "This kept my 2 year busy for an entire hour and my 4 year old busy for 2 hours! YAY! Drop vinegar tinted with food coloring onto a pan filled with baking soda. Sheer minutes of colorful fizziness!