Summary The Shoebox Regatta teaches physics with 3D-printed toys. Teach kids how sailboats work by making Catamaran sailboats from printed parts, soda straws and plastic wrappers. The boats can be raced with each in a plastic shoebox of water and powered by blowing on the sails through straws. Adjusting the sail (lateen rig like a sunfish), rudder and wind direction facilitates learning of how sailboats can sail in directions other than the way the wind is blowing. Instructions -Print the set of sailboat parts (designed to fit on the small Printerbot Simple bed) -Cut 4 equal straw pieces (3 long) for pontoons -Cut a 1 inch straw for centerboard support -Cut a 3 inch straw for mast -Cut triangle sail from cellophane and tape to printed spars -Assemble sailboat -Fill plastic box half full of water. -Float in water and adjust tiller and sail for broad reach. -Gently blow on sail through a straw. -Each boat in the regatta has a shoebox and the sailers provide their own wind at the starting signal. -Winner is the first boat to go the length of the box without touching the side. -Winner of the tournament (regatta) gets to keep the winning boat (which is replaced in the fleet by the one printing during the competition.) Materials : -3D printed parts: sail spars, forward frame, aft frame, centerboard, rudder and tiller. -4 colorful soda straws. -colorful cellophane food packaging -plastic shoebox and water Lessons include: -center-of-gravity -angle of incidence and resulting forces on the sail, -how to steer a sailboat to go other than the way the wind is blowing, -the iterative design process for improving performance, Teachers can re-use the apparatus with subsequent classes.