Snorkeling
John and I were able to go snorkeling everyday we were there. (except sundays!) And we loved it. We went to a different beach each time and saw probably every fish there was to see!
Monday, the 2nd day we were there, we went with a group of friends on a pontoon raft tour to see the lava caves/lava tubes. Snorkeling in 2 different spots and then over to Molokini - the crater just off of Maui with at least 20' crystal clear visability. We were even able to see sharks - it was really cool!