Welcome to cruise chat mccormick, well let me just tell you there are loads of things to do on a ship from working out to swimming, dancing, eating and relaxing and believe me there are a lot of things I didn't even mention you will have a great time.
Just try to sit back & relax although I doubt if you will. I usually get home exhausted & need another vacation to recoup. Don't eat to much. (I should talk- )
Definitely read the ship's newsletter about things to do. You will no doubt find yourself torn about all of the choices and will often find that there is more than one activitiy going on at the same time that you would love to do. If on Royal Caribbean, the Love and Marriage game show is a must see. I don't think that I have laughed that hard in a long time.