The SS United States, a history ocean liner from the 1950s and 1960s is just a couple of months from being sold for scrap unless more money for its restoration can be raised. Check it out and contribute if you feel led. These old ships hold a fascination for many, and are such an important part of our maritime heritage.
Fox News has a writeup of the current situation.
I mentioned this great hands-on museum in an earlier post, but wanted to explicitly point it out. Right on the river in downtown Norfolk, VA, you can learn a lot about various maritime activities, from shipping to naval history. Parts are open for free admission, while others have a fee.
The Hampton Roads Naval Museum is on-site in the same building and admission to this section is free.