Bank of America has a program called Museums on Us. It used to be that they picked one weekend a year and you could get into a bunch of museums for free by showing your bank card. Now they’re doing it every first weekend of the month. Some of the big museums like the MET want you to donate $20 to get in so this is good way to get some free culture.
http://promotions.bankofamerica.com/museums/
In the NYC area they’ve got Liberty Science Center, the MET, Newark Museum, Bronx Zoo, New York Aquarium, etc.
