Since New York City is very close to us, I thought it would be nice to include these New York City museums. They are either always free, free on specific days of the week or free for select hours.
Find one near you when you are visiting the big apple, and take advantage of their generosity.
Note that this takes into account general admission only; certain events and special exhibitions may still require a fee.
More information here: http://www.nycgo.com/articles/free-nyc-museums
Also, there is this free guide to New York City museums. Very helpful!
Finally, here is a PDF version of the article in case it disappear from the internet: