This is one of two NYC-centric history museums I belong to. The Museum of the City of New York is the other. The Historical Society has permanent interactive history exhibits on the first and fourth floors. It also has a permananent Tiffany lamps collection on display. The Women's History Center has had several great exhibits.
This was an emotional exhibit for me. I was a teenager in the 80's when the AODS crisis hit, and I remember the confusion, bigotry, and cruelty that came with it. This exhbition went into all of that in excruciting detail, from medical researchers trying to isolate what caused AIDS and prevent the spread of the disease to the religious right using AIDS to vilify the gay community, saying that AIDS was God's punishment of gay men. I left this exhibit in tears.