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.
Step-By-Step Boat Plans - DIY Wood and Metal Pipe Blanket Ladder - 13 Binder Planner DIYs to Organize Your Stuff - Master Boat Builder with 31 Years of Experience Finally Releases Archive Of 518 Illustrated, Step-By-Step Boat Plans