The Museum began the summer with a series of five individual projects diverse enough to satisfy the interest of any child out early from school. Flashy pinball machines told adventure stories. Battery-powered cars, dressed up like animals, spaceships, and bulldozers, changed direction at the flick of a switch. On Wednesday, students tested their castle construction skills as fortified walls complete with working drawbridges rose up above murky moats. Boats and sea monsters braved rough water, and robots spun and waved their arms in elaborate dances.