We went kayaking in the bay on our own in the morning. It was a nice experience but bear in mind that you can't land the kayak or snorkel from it. We went on the Sacred Sites tour. The guide was quite nice and well informed. We enjoyed the tour. We also got to see the blue-eyed eels that the guide fed.
We went on the motorized outrigger canoe and 4x4 tour. The canoe tour was nice. You go up the river which is not very deep and then come back out. The 4x4 was ok but the guide didn't speak English very well. We ended up speaking French.
We did a single dive here in Moorea. The dive was the "Shark Gallery." This dive was outside the barrier reef and was in some pretty rough seas. Once we got down however, the experience was wonderful. There were too many black tipped sharks to count. They get pretty curious and come quite close. Since our other excursions were ruined, we rented a car ($80) the second day and just traveled the island.