Taking the Plunge: Don mask, fin, and snorkel and explore the magical world beneath the surface, where you'll find exotic corals and kaleidoscopic clouds of tropical fish; a sea turtle may even come over to check you out. Can't swim? That's no excuse -- take one of the many submarine tours offered by Atlantis Submarines (tel. 800/548-6262; www.go-atlantis.com) on Oahu, the Big Island, and Maui.

Meeting Local Folks: If you go to Hawaii and see only people like the ones back home, you might as well not have come. Extend yourself -- leave your hotel, go out and meet the locals, and learn about Hawaii and its people. Just smile and say "Owzit?" -- which means "How is it?" ("It's good," is the usual response) -- and you'll usually make a new friend. Hawaii is remarkably cosmopolitan; every ethnic group in the world seems to be represented here. There's a huge diversity of food, culture, language, and customs.

Feeling History Come Alive at Pearl Harbor (Oahu): The United States could turn its back on World War II no longer after December 7, 1941, when Japanese warplanes bombed Pearl Harbor. Standing on the deck of the USS Arizona Memorial (tel. 808/422-0561; www.nps.gov/usar) -- the eternal tomb for the 1,177 sailors and Marines trapped below when the battleship sank in just 9 minutes -- is a moving experience you'll never forget. Also in Pearl Harbor, you can visit the USS Missouri Memorial; World War II came to an end on the deck of this 58,000-ton battleship with the signing of the Japanese surrender on September 2, 1945.

Watching for Whales: If you happen to be in Hawaii during humpback-whale season (roughly December to April), don't miss the opportunity to see these gentle giants. A host of boats -- from small inflatables to high-tech, high-speed sailing catamarans -- offer a range of whale-watching cruises on every island. One of our favorites is along the Big Island's Kona Coast, where Capt. Dan McSweeney's Year-Round Whale-Watching Adventures (tel. 808/322-0028; www.ilovewhales.com) takes you right to the whales year-round (pilot, sperm, false killer, melon-headed, pygmy killer, and beaked whales call Hawaii home even when humpbacks aren't in residence). A whale researcher for more than 25 years, Capt. Dan frequently drops an underwater microphone or video camera into the depths so you can listen to whale songs and maybe actually see what's going on.

Creeping Up to the Ooze (Big Island): Kilauea volcano has been adding land to the Big Island continuously since 1983. If conditions are right, you can walk up to the red-hot lava and see it ooze along, or you can stand at the shoreline and watch with awe as 2,000°F molten fire pours into the ocean. You can also take to the air in a helicopter and see the Volcano Goddess's work from above.

Going Big-Game Fishing off the Kona Coast (Big Island): Don't pass up the opportunity to try your luck in the sportfishing capital of the world, where 1,000-pound marlin are taken from the seas just about every month of the year. Not looking to set a world record? Kona's charter-boat captains specialize in conservation and will be glad to tag and release any fish you angle, letting it go so someone else can have the fun of fighting a big-game fish tomorrow.

Greeting the Rising Sun from atop Haleakala (Maui): Bundle up in warm clothing, fill a thermos full of hot java, and drive up to the summit to watch the sky turn from inky black to muted charcoal as a small sliver of orange light forms on the horizon. There's something about standing at 10,000 feet, breathing in the rarefied air, and watching the first rays of sun streak across the sky. This is a mystical experience of the first magnitude.

Riding a Mule to Kalaupapa (Molokai): If you have only a day to spend on Molokai, spend it on a mule. The trek from "topside" Molokai to Kalaupapa National Historic Park (Father Damien's world-famous leper colony) with Molokai Mule Ride (tel. 800/567-7550; www.muleride.com) is a once-in-a-lifetime adventure. The cliffs are taller than 300-story skyscrapers -- but Buzzy Sproat's surefooted mules go up and down the narrow 2.9-mile trail daily, rain or shine, and have never lost a rider or a mount on the 26 switchbacks. Even if you can't afford to mule or helicopter in, don't pass up the opportunity to see this hauntingly beautiful peninsula. It takes nothing more than a pair of hiking boots, a permit (available at the trailhead), and some grit to hike down the trail. The views are breathtaking: You'll see the world's highest sea cliffs and waterfalls plunging thousands of feet into the ocean.

Taking a Day Trip to Lanai (Maui): If you'd like to visit Lanai but have only a day to spare, consider taking a day trip. Trilogy (tel. 800/874-2666 or 808/661-4743; www.sailtrilogy.com) offers an all-day sailing, snorkeling, and whale-watching adventure. Trilogy is the only outfitter with rights to Hulupoe Beach, and the trip includes a minivan tour of the little isle (pop. 3,500). See p. ###. You can also take Expedition's Lahaina/Lanai Passenger Ferry (tel. 808/661-3756; www.go-lanai.com) from Maui to Lanai, then rent a four-wheel-drive vehicle from Dollar Rent-A-Car (tel. 800/588-7808) for a day of backcountry exploring and beach fun.

Soaring Over the Na Pali Coast (Kauai): This is the only way to see the spectacular, surreal beauty of Kauai. Your helicopter will dip low over razor-thin cliffs, fluttering past sparkling waterfalls and swooping down into the canyons and valleys of the fabled Na Pali Coast. The only problem is that there's too much beauty to absorb, and it all goes by in a rush.