There are participating museums and galleries in every state. That includes major, must-see institutions like the American Museum of Natural History, the Newseum, the Denver Art Museum, the Adler Planetarium, the Motown Museum, the Metropolitan Museum of Art, the Whitney, the Andy Warhol Museum, and the Intrepid Sea, Air, and Space Museum.
The program is, unfortunately, limited to card-holders. However, if you're not a member, you don't have to Night at the Museum your way into a building to get a free admission. Smithsonian Magazine's annual Museum Day is coming up on September 22. The massive celebration of museums had more than 1,800 institutions open its doors for free last year.