Guys, if you have hairy legs... don't shave them! You would be a ringer in the hairiest leg competition.
Yes there are videographers. They lurk around the ship. AVOID THEM AT ALL COSTS or you will end up watching yourself on the onboard TV station along with every other passenger. However it could be your one and only chance at your 15 minutes of fame. If that is the case... make sure you have had a lot to drink to make it a memorable moment for all of us.
It is not recommended that you flush the commode while sitting on it. If you want to see what I mean, try it. If you go up to the pool deck the first night or early in the morning when people have their bathing suits on, you can tell who has tried this little experiment by the red marks on their upper thighs. By the second day most people have learned their lesson so catch the sights early in the cruise.
Make sure you get a map of the ship as you walk onboard. Without it you will be doing a great imitation of Stevie Wonder for about 4-5 days or better yet leave the impression that you have a very bad drinking problem. Carnival has a great knack for cramming a lot of stuff into a lot of space. Don't be one of those passengers who finally figure out where everything is on the day the cruise ends.
For kicks, set your alarm clock for 4 in the morning and call room service and ask for two lobster tails and drawn butter. YES they will deliver them to you within 30 minutes.
Yes, bring a bungee cord to hold open your balcony door if you have a balcony room. Makes for a nice night of sleeping when you can have the door open. Without the bungee cord the door slams shut. You will get to know THAT noise pretty quick, as your neighbors will make you fully aware of it.
First time cruisers, buy BONINE at your local drug store before you leave home. Start taking the pills in the morning the day of the cruise. Even though these are huge ships and have underwater stabilizers (huge wings that extend out like airplane wings), the ship DOES rock. It will take you a day or so to really feel comfortable. However remember one thing. The worse time you will have with the rocking will be after you get home from your cruise and you are in the shower. BY GOD HOLD ON FOR DEAR LIFE! (***)
Yes, to be a hero on Carnival, you MUST enter every contest, competition and game they have going. If you can snag more than 3 ship-on-a-stick trophies... YOU DA MAN!
Be prepared to see some of the most ingenious things that can be made out of your bathroom towels. Yes, you will find cute towel monsters on your bed during the entire cruise.
YES you must pay for your drinks in the casino. Sorry... There are no freebies in the alcohol department. There are however "daily drink specials" I think they forget to put alcohol in them though.

(***) Real simple why you rock in the shower for a couple of days after your cruise: The fluid in your inner ear counter balances the rocking on the ship. This is the way your body gets used to the rocking onboard. When you are on land, even though you are stabile, the fluid is still rocking. It really only shows up dramatically when you close your eyes and tilt your head back. When are you most likely to be doing that ?? Rinsing the shampoo out of your hair in the shower.