Akaka Falls, 420 feet high, is one of several spectacular waterfalls along the Hamakua coast of the island. It's the easiest one to get to, and the trip there has a little bonus—you'll have to pass Honomu, a tiny-but-sweet country plantation town.

From May to October, big-game tournaments, with prize money totaling up to $1,000,000, inspire an atmosphere as competitive as the World Poker Championship. Newbies who want a taste of the hunt for monster-size marlin, wahoo, mahimahi, and tuna can charter a boat (they're easy to come by, thanks to the high density of sportfishers who live here year-round). Otherwise, the friendly folks at Kona Sea Sports offer sportfishing tours, in addition to snorkeling, diving, and swimming with dolphins. They practice "catch and release" for the big billfish (unless the fish are severely injured), but any fish you catch under 50 pounds is yours to keep. Booking two weeks in advance is recommended.

With more than a dozen world-class courses, the Big Island is Hawaii's premier golf destination, known for tricky shoreline holes (the classic shot over water and lava field onto the green), challenging winds, and rolling hills. Greens fees for the Kohala courses are akin to highway robbery, although guests pay less when they play where they're staying. Playing is much more affordable on the more modest Waimea, Volcano, and Hilo courses. Due to the blazing sun, it's best to tee off in the morning, but golfers who can stand the heat can take advantage of discounted greens fees after 3 pm.

Damage sustained during a 2007 earthquake closed the Kohala Coast's Mauna Kea Beach Hotel and its 1964 Robert Trent Jones, Sr., golf course (the standard of excellence in these parts), but there are still many more to choose from. In Kailua-Kona, the Jack Nicklaus–designed course at the Hualalai Golf Club is relatively protected from the wind and is one of the most player-friendly courses on the island (open only to Four Seasons guests). The ocean- and lava field–views from the popular, well-maintained Mauna Lani Francis H. I'i Brown South Course in Waimea may distract you from your game. The Waikoloa Kings Course is tough, with many lava obstacles, but also stunning 360 degree views. Close to Kohala, the Waimea Country Club is affordable, and generally cooler temperatures mean you can play all day; as long as mist, fog, and rain don't cut your outing short. At 40,000 feet above sea level, the Volcano Golf & Country Club can be chilly and sometimes wet; unlike at most other courses, afternoon rounds are favored over morning play and there's very little wind. Locals are the usual foursomes at the small, nine-hole Hamakua Country Club—it's casual, great for beginners, and since Hilo is one of the rainiest places in the state, the course is always lush.

Located eight miles north of Hilo at Onomea Bay, this lush garden is composed of easy-to-navigate nature trails running through a rain forest of rare and endangered flora. Beautiful and buggy—be sure to bring deet.

Open daily 9 am to 5 pm; last entry at 4 pm.

If you had to have one defining reason to go to the Big Island, the erupting Kilauea caldera would be it (lava-spewing Puu Oo crater went on a brief sabbatical in 2007, leaving Kilauea dry for the first time in more than 20 years, but the dry spell was short-lived). Nearly two million people visit Hawaii Volcanoes National Park each year. Looking at the lines of cars parked on the Chain of Craters Road and people hiking in while carrying gifts, you'd think aliens had landed; most of these pilgrims bring water, cameras, and offerings to the volcano goddess, Pele (be mindful not to litter in the park). You can't get as close as you could in past years, but it's still so hot you may feel as if you're dinner walking on the grill. Get situated before sunset to see the molten lava fingers glowing red down the hillsides and flowing into the sea. Over half of the park is designated an International Biosphere Reserve and a World Heritage Site and is great for hiking. Camping is allowed, and there's Volcano House, a very decent restaurant and hotel inside the grounds (Crater Rim Dr.; 808-967-7321; www.volcanohousehotel.com). Driving and hiking will get you close to the active flow, but only a helicopter can transport you directly over the crater for a look in. Blue Hawaiian Helicopters is the island's most established operation and absolutely worth the money. If you're prone to motion sickness, take precautions before boarding the aircraft for the 50-minute "Circle of Fire" and waterfall tour.

Next to the Kilauea Visitor Center, the Volcano Art Center gallery is run by a nonprofit organization and holds workshops, classes, special events, and local art exhibits (Crater Rim Dr.; Hawaii Volcanoes National Park, Volcano; 866-967-7565; www.volcanoartcenter.org).

Well-marked and challenging trails crisscross Volcanoes National Park (you'll get a map upon entering), including the popular hikes down and across Kilauea Iki Trail, to Napau Trail, along Byron Ledge and the daylong Crater Rim Trail (808-985-6000; www.nps.gov/havo). Lightweights and families can try the 15-minute trek along the Malama Trail, just north of the Mauna Lani resort, to see Hawaiian petroglyphs. For the really hardy, the steep walk down and even more exhausting hike back up the Waipio Valley is worthwhile—it's a sacred spot to Hawaiians.

This mill sits not in Hilo but on 24 verdant acres in the blink-and-you'll-miss-it town of Mountain View just south on Highway 11 (chances are you'll smell the place before you see it). Green coffee beans from family farms throughout the state are processed here in small batches, packaged on-site, and distributed to many of the island's best restaurants. Stop into the café to power up for an outing to Hawaii Volcanoes National Park (the mill is on the way) and get a quick tour of the entire process, or just purchase some bags of beans to take home.

Open Mondays through Fridays 7 am to 4 pm, Saturdays 8 am to 4 pm.

All kitsch, all the time. Named after a 1930s entertainer and hula dancer, this emporium is one-stop shopping for Hawaiian music CDs, his and hers Hawaiian shirts, tiki home decor, Hello Kitty Hawaii, even mini ukuleles. And free coffee and shell leis when you walk in the door. Check the Web site for additional locations.

Open daily 8:30 am to 6 pm.

The world's largest collection of telescopes (13) on top of Hawaii's highest mountain, Mauna Kea, has long distinguished Hawaii as a mecca for astronomers. For the rest of us, the Imiloa Astronomy Center at the University of Hawaii's Science and Technology Park in Hilo strives to make a powerful connection between the expertise of the indigenous Hawaiians who navigated by the stars and advancements in the field today. Visitors begin with a planetarium show called Mauna Kea: Between Earth and Sky, which raises as many questions as it answers about the origin of the universe, then walk through interactive displays. Kids under 5 won't get much out of the place, but it is a good rainy-day activity, and in Hilo, those days come frequently. The café (open to the public) has a growing local following and is a good place to grab a quick, tasty lunch.

Open Tuesdays through Sundays 9 am to 4 pm.

Every year in October, the Kohala Coast hosts the awe-inspiring Ironman Triathlon world championship: a 2.4-mile ocean swim, followed by a 112-mile bike ride through a lava field, followed by a 26.2-mile run—all executed in one day under the blazing sun. (Spectators should be aware that there isn't much sun cover on the sidelines either.) For a week before and a week after the event, the quiet coast bustles with camera crews and some of the most hard-core athletes you'll ever meet. And not just energetic twentysomethings—there are triathletes who compete through their 60s. After the event, the whole bay-front strip of Alii Drive turns into an Ironman after-party.

In addition to raising grass-fed livestock that you've probably already eaten in a nice restaurant on the West Coast, Kahua Ranch—8,500 acres on the northern end of the island—operates a renewable-energy enterprise, ATV tours, and its own retail store, where it sells everything from ranch wear to beef and lamb chops. The ATV tours are nothing to write home about, but it's worth stopping by to get schooled by a paniolo (Hawaiian for cowboy).

Open Mondays through Saturdays; by appointment only.

Mauna Kea, 14,000 feet above sea level, is the highest peak on the island. It's an all-day affair to drive up there, and definitely worth it if there's snow (for the novelty value). But the air is thin—you may suffer from altitude sickness—and you should bring your own supplies. The summit of Mauna Kea is recognized as one of the world's best places to observe stars, so about a dozen of the finest telescopes are situated here, along with some of the world's best astronomers. Most of these facilities are for experts only, but there are free tours on Saturday and Sunday, and the visitors center hosts a stargazing program nightly from 6 to 10 pm.

Open daily 9 am to 10 pm.

Held the week after Easter in Hilo, this is the showcase and competition for the best and the brightest stars of the hula dance world. It's traditional, authentic, intense Hawaiian hula with strong chanting and rhythmic drumbeats. Amazing to behold, the guardians of Hawaiiana and many in the Hawaiian community attend in all their finery, but that means there's not a lot of room for tourists. Also broadcast on local television.

Held Thursday, Friday, and Saturday evenings the week after Easter.

In Hawaii, tsunamis, more than any other natural disaster, have been responsible for killing the most people. From 1900 to 1964, small tidal waves hit Hilo every seven years. A 1946 tsunami destroyed beachfront neighborhoods, flooded downtown, changed the coastal landscape, and killed about 159 people. This museum stands as a memorial and a source of information to demystify the big-wave phenomenon.

Open Mondays through Saturdays 9 am to 4 pm.

Founded in 1847, Parker Ranch is one of the oldest and largest privately owned ranches in the United States. Because a drive through Waimea affords views of the lands, an official tour may seem redundant; but it's worth a stop for an ATV tour, horseback riding, hunting, and the often overlooked but delightful Parker Ranch Historic Home Tour. The home tour includes a brief history of John Palmer Parker, who befriended King Kamehameha, married a Hawaiian princess and built the ranch, and a walk through the family's original wood cabin, Mana Hana. In a radical jump from past to present, the tour also includes a walk through the Puuopelu estate of Richard Parker Smart, last descendant to live on the ranch (until the late '80s). A Broadway actor before resettling on the Big Island, Parker Smart collected Impressionist art while traveling abroad and amassed one of the most impressive private collections in the state.

Contrary to popular belief, there's good surfing on the Big Island, mostly along the west side from Kawaihae to Captain Cook. The problem is that the breaks aren't easy to access. Two (often crowded) exceptions to this rule are Banyans, clearly visible from Kona's Alii Drive (just south of the Kona Bali Kai Hotel), and Honolii, visible from Highway 19 about five minutes outside of Hilo (turn into the Alae Point community and drive down toward the water). Highly skilled wave riders should seek out Pine Trees on the Kona side of the island off Highway 19: Take the dirt road near mile marker 94 (you'll need a truck or 4WD) to the Natural Energy Lab, then follow the dirt road off the parking lot for about a mile until you see the break—there actually aren't any pine trees to mark the spot. Visitors should bring drinks and snacks to share with the territorial locals. For newbies, Kahaluu Beach Park in Kona is one of the best spots for beginners and surf lessons.

This hidden valley can be viewed from an outlook near Honokaa when driving along the Hamakua coastline, but if you want to see the idyllic, untouched wonder up close, the road down is pitched at a ridiculously steep 45-degree angle. Even with a four-wheel drive, you'll be better off in the hands of professionals. Try the Waipio Valley Wagon Tours held at 10:30, 12:30, and 2:30 Mondays through Saturdays, September through April; Mondays through Fridays May through August (45–3625 Mamane St.; 808-775-9518; www.waipiovalleywagontours.com). Don't even think about walking it unless you're training for the Ironman Triathlon—your knees will be totally blown out by the time you get to the bottom, and then how in the world will you get back up?