cardboard tubes + box = hours of fun! We pieced together TP and paper towel tubes. Used marbles. The kiddo loved it and even still pulls it out to roll the marbles into a dump truck. He wont' let me toss any cardboard tubes now.
DIY Rocket ship photo booth at a space themed birthday blast off party. Use a few cardboard boxes covered in blue plastic tableclothes and spraymount a foamcore rocket ship on front. Cut a porthole in.