What dates are you going? Spring break? Be sure to go on a Humpback Whale boat tour in the water off Ka anapali beach. There a hundreds, maybe thousands of whales in the shallow waters birthing their young. Really neat. Take the drive to Hana. It s lovely.On Oahu, got to the north shore and watch the surfers. If you are a surfer try it, but it s only for advanced surfers.
I agree with Patriotgal, but I d like to add some more suggestions. These all apply to Maui since I haven t been to Oahu.Go snorkeling (or scuba diving if you re certified). There are some excellent snorkeling beaches along the southwest shore of Maui, south of Kihei and Makena. If you re the adventurous type, go to Little Beach, my favorite clothing-optional beach and a great place for snorkeling and body surfing.Go to the Iao Valley. It s very scenic and it s just a short climb to a vantage point where you ll have a fantastic view of the Iao Needle. It s actually the end of a long narrow ridge, but viewed from the end it looks like a needle. There are also some charming Asian gardens there, including a Japanese garden with a Koi pond and a stand of bamboo you can walk through.Watch the sunrise from the top of Haleakala, the 10,000 foot extinct volcano. If you re brave you could even bicycle down it. Just make sure the brakes are in good working order and watch your speed. You wouldn t want to get out of control. I haven t tried it but I ve driven on that road and I know it s steep and has a lot of hairpin turns.Go to the Maui Ocean Center. If you don t snorkel or scuba dive, it s the closest thing to it without getting wet. The main attraction is a huge tank full of sharks, rays, and other fish with a transparent tunnel running through it. It s an awesome experience to walk through and see big stingrays swimming over your head and sharks adn fish all around you.Go sightseeing in Lahaina. It s an old whaling town that s been turned into a tourist attraction. It still retains a lot of the old architecture and you ll see old-fashioned sailing ships in the harbor. It also has Hawaii s largest banyan tree. A tree may not sound like a big deal but this one is amazing. It takes up a whole city block and has numerous trunks that grew down from the branches over the years. Lahaina is also a great place to go for dinner or a luau. Some of the islands best luaus are there, along with fun restaurants like Bubba Gump Shrimp Company and Cheeseburger in Paradise.Two other restaurants I d recommend are the Big Wave Cafe and Kai Ku Ono (KKO), both in Kihei. KKO has better food, but the Big Wave Cafe is a real bargain if you get there early in the evening and take advantage of their two for the price of one entrees.
In waikiki (and possibly other areas but I m not to sure), there s a restaurant called cheeseburger in paradise, it is very very good, I highly rec comend it! Pearl Harbour, Waikiki Aquarium and Zoo, and shopping at all the boutiques are all fun things to do as well. Also When we were there I heard going up to the North shore is really neat, but we ran out of time. That s my one regret is not being able to do that.