I have nearly pissed myself reading some of the comments on this thread. You guys are hilarious! Anyway, Rev, be sure that you sign up as soon as possible
for the shore excursions. The good ones fill up ultra fast.
Like someone said, you can bring your own liqour on the ship. IMHO, it can be a pain in the ass to get refills if you're soaking in the sun on the deck. I have brought my own in the past, but used it only for pre-dinner cocktails and a nightcap. Other than that, it's so much easier to buy the drinks at the ship's bars. It won't interfere with your fun.
I concur with Stingray City in the Caymans. It has been 8+ years since I have visited Cozumel, but my wife and I met our best friends in the world while getting off the ship in Cozumel, so it has a special place in our hearts. We ended up going to Carlos & Charlie's, getting rip-roaring drunk and screwing like rabbits the second we got back to our cabin.
Get involved with some of the late-night young adult activities on the boat. We've done toga parties, comedy shows, game shows, etc. They're a great time!
Have fun and bring your sunscreen! The sun in the Caribbean is nothing like it is in the States...much more powerful!