Nothing ground breaking for me in this department, I like relaxing, pool, beach, and ocean. Not necessarily in that order. I like the beach at the resort but also enjoy offsite beaches.
We did enjoy our hike up the volcano, golf, and touring the island. Also enjoyed the beachside bars that are walking distance from resort.
I know you only asked about activities but some of my other observations are:
The timeshare is fully integrated with the hotel pools, fitness center etc. And the units are physically located within the (no separation) hotel grounds. This means there is a short walk to bars, restaurants, coffee shop, spa etc. I also like the layout and spaciousness of the units and the staff is great. The beach is large and plenty of palapas are available.