The New York CityPASS includes two standard attractions: the Empire State Building and the Museum of Natural History. In addition to these two visits, you can then choose three attractions from a selection of six options (a 2-hour cruise on the Hudson River, the ferry to visit the Statue of Liberty and Ellis Island, the Air and Space Museum and its aircraft carrier, the Top of the Rock observatory, the Guggenheim Museum and the 9/11 Memorial).
As you can see, the New York CityPASS gives you access to five of the city's top attractions at a lower price than if you had paid for each activity separately. According to the official website, you save 39% by buying the pass!