Regular 'ol scuba diving in St. Maartin is a blast, too! My fiance & I took a scuba diving excursion for inexperienced, non-certified divers in Dec. of '06 and had a FANTASIC time.
We wanted to do something crazy and out of the ordinary (for us), and it was the perfect choice. There was one dive instructor for every 4 people, though we got lucky and had an instructor all to ourselves. Good thing, too -- I ended up being terrified after I got all the gear on and definitely needed one-on-one attention! He was very patient and was by my side every step of the way. We ended up going down about 25 ft. and saw some amazing sights. Never be afraid to try something new when you're in a new place.