I don't know if the person asking about activities in Hawaii has already gone, but my husband and I were in Maui a long time ago and got the chance to do a bunch of great things. I imagine they're still available. One was a helicopter ride which took us up and down the island zooming in on long, ribbony waterfalls and then flying low over the treeline before veering out over the water. As someone who is not a thrill-seeker, I found it a bit frightening at first, but then it became exhiliarating. My husband liked it from the first second of the ascent. We also got a video of the entire experience which is fun to look back on today.
Another experience was a day-long horseback ride with a picnic lunch and a swim in a private lake fed by a cascading waterfall. Even my husband, who had only been on a horse once before, got a kick out of the whole experience. The guide was an old hippie who had a stable of beautiful horses. I think we went out with about 10 people and had an amazing experience.
I would recommend either one of these adventures!