I believe the Adventure Ocean program is included in the price of the cruise. Your cruise price includes meals in either the main dining room or the Windjammer, stateroom accommodations, and nightly entertainment.
Most activities onboard the ship, such as ice skating, rock climbing, and the pools are also included in the price of the cruise. Bingo you would have to pay for, if that's something that you like to do.
As far as dining, the dining venues that are included in the price of your cruise would be the main dining room and the Windjammer cafe. Other restaurants onboard the ship would be extra. You don't mention the name of the ship, but if it has a Cafe Promenade, there are some items there that are free, and some you have to pay for. I believe specialty coffee there you have to pay for, but if it's just regular coffee, that's free.
The only beverages included in your price would be water, iced tea, and I think coffee. Alcohol and soda you have to pay for. If your son drinks a lot of soda, then you might consider a soda package. That is unlimited fountain soda for $6.00 per day. However, you would have to drink at least 3 cans of soda per day (what they would usually give you without the package), in order for that to pay off.
2007 - Majesty of the Seas
2009 - Enchantment of the Seas
2010 - Freedom of the Seas