If you like Parasailing or snorkeling, then definitely try to do those while you're in either Nassau or CocoCay. While you're in Nassau, definitely try to go over the bridge to see Atlantis and Paradise island. It shouldn't be a very expensive cab ride at all, especially if you share with another party that wants to go over there.
Other than that, it really depends on what you want to do. Mainly just relax and have fun!
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)