I love sneaking over here in the middle of the day to see a movie - they always have the best selection of films. I recently saw Pina in 3D and The Kid with a Bike here, and another time I saw Bela Fleck play the banjo after a screening of Throw Down Your Heart.
You can't say you've seen NYC until you've seen it from a boat. Hop on the ferry from anywhere to anywhere and you'll see what I mean. Not only will you see excellent old buildings and factories--the inner workings of the old industrial city--but you'll head out under working bridges and see the skyscrapers in all their towering glory. And once you've done it, do it again, at night.