One of my favorite places to visit on Oahu is Kualoa Ranch on the Windward side of the island. It is a working cattle ranch whose owners have dedicated themselves to keep the ranch, including its two majestic valleys and large fishpond free of commercial development and in as natural a state as possible.
In order to accomplish this goal, the ranch has developed a number of activities/tours which have become more and more popular every year. These include a Hawaiian Experience tour, Movie Site & Ranch tour, Jungle Expedition, Fishpond & Garden tour as well as ATV tours and 1 and 2 hour horseback rides.
The ranch is also available for concerts, weddings, corporate events and has, in recent years, become a major filming location for both motion pictures (50 First Dates, Godzilla, Jurassic Park and more) and television (Lost, Hawaii Five-0, and the new The Last Resort.)