Are you looking for a fun game to play that will keep the kids busy? These Balloon Cup Shooters are awesome! And they will definitely keep the kiddos entertained for a few hours. All you need are plastic cups, balloons, duct tape and ping pong balls.
DIY Turn PVC pipes into a playground musical instrument. I wish this had the instructions with it, but I might be able to figure it out. This might even work as a service learning project for my daughters' school.