Take a sport fishing boat out to catch your dinner. Sail to Lanai for the day to snorkel and laze around on deck.
Scuba dive the pristine waters of Hawaii's only barrier reef.
Play 18 holes on one of Hawaii's five best golf courses. Or maybe a fast nine on the local municipal course. If you didn't bring yours, rent some gear and go snorkeling, surfing or boogie boarding. Tenderfoot or experienced, sign up for a horseback adventure. Rent a mountain bike and go touring.