Cardboard Surfboard

34-year-old Mike Sheldrake (above) invented it.

"A Sheldrake board is stunningly transparent. Its core is a matrix of ribs running three directions. There's no foam, just fiberglass skin over computer-cut cardboard," wrote Keith Hammond in an article in issue #19 of Make magazine.

Added Hammond, "Best of all, instead of buying $900 boards, he can now make them for about 150 bucks."