Given: 10 marbles, table or other raised surface from which to start, cardboard-flat and tubes, paper plates, construction paper, egg cartons, plastic cups, nails, push pins, masking tape, sponges, tacks, various boards, small boxes, 8 foot and / or shorter pieces of plastic molding for paneling or other supplies as desired and available.
Design and build a marble run with as much variety as possible. At the end of the allotted time (10-30 minutes), run 10 marbles and judge the run on variety, creativity, and engineering. The problem might be altered to give more points for very slow descent of the marbles.