The ancient Hawaiian sport of hee nalu ("wave sliding") is probably the sport most people picture when they think of the islands. You, too, can do some wave sliding -- just sign up at any one of the recommended surfing schools listed below.
Always wanted to learn to surf, but didn't know whom to ask? Call the Nancy Emerson School of Surfing (tel. 808/244-SURF or 808/874-1183; www.surfclinics.com). Nancy has been surfing since 1961, and has even been a stunt performer for various movies, including Waterworld. She's pioneered a new instructional technique called "Learn to Surf in One Lesson" -- you can, really. It's $70 per person for a 2-hour group lesson; private 2-hour classes are $140.
In Hana, Hana-Maui Sea Sports (tel. 808/248-7711) has private lessons taught by a certified ocean lifeguard for $79 for a 2-hour lesson.
Expert surfers visit Maui in winter when the surf's really up. The best surfing beaches include Honolua Bay, Lahaina Harbor (in summer, there'll be waves just off the channel entrance with a south swell), Maalaea (a clean, world-class left), and Hookipa Beach, where surfers get the waves until noon; after that -- in a carefully worked-out compromise to share this prized surf spot -- the windsurfers take over.