Above is a video of my friends and I got the opportunity to Scuba dive the Oriskany aircraft carrier off the coast of Pensacola, FL. This dive is pretty amazing. It is one of those locations that you could dive 100 times and find something new every time. As of 2008 it was the largest vessel ever sunk to make a reef. It's bigger than the Titanic.
The flight deck is at 135 feet which means recreational scuba divers cannot stand on it. That doesn't matter though since the ship is gigantic. You can hover above the flight deck, or if you would like your dive to last longer you can hang out on the tower which starts at 80 feet. Whether you're a technical diver or a recreational diver this site has tons of goodies.
If spare time is in your immediate future you should check out the wikipedia page on the Oriskany.