Take a day trip to the mainland and do the combo zip-lining and cave tubing excursion. Most tour companies offer this combo trip. A great experience!
Lamani (Maya ruins) trip with Tanisha Tours. Fantastic!
On the island.....snorkeling, diving, parasailing, kayaking, fishing. Lots of great restaurants. Live music most every evening somewhere along the beach/restaurants/bars. Chicken drop at Wahoo's on Thursday evening. Casino at Captain Morgan's.
Full-day private catamaran trip with barbecue lunch on El Gato. Favorite thing to do!
Look on ambergriscaye.com for links and information on most of this stuff.
Have a blast!