A surfboard was a flat board used in the Earth sport of surfing.
In the late 20th century, one brand of surfboard was McCoy. (VOY: "Future's End")
In the 2120s, Banzai Pipeline Surfboards were available on Earth. (TNG: "Up The Long Ladder")
In 2368, Geordi La Forge compared the flight of a starship on Soliton waves to riding a surfboard. (TNG: "New Ground")