This drive up the northeast coast of Oahu is just about the most beautiful road in the world! $5 will get you out and back. At the end of the line you can eat in the little village and then the return bus goes through the centre of the island, past Schofield barracks (where From Here to Eternity was set) and the Dole plantation. It takes a good part of a day, but was really worth it. Tropical paradise!