Coney Island is the best for everything - the beach, the rides, the beer - but mostly for the Skee Ball. It's incredibly addicting, affordable and satisfying (depending on your aim).
The rooftop garden at the Metropolitan Museum of Art. The museum floors below are a maze of tremendous art and inspiration, and taking the elevator to the rooftop garden is the icing on the cake. 360' views of verdant green Central Park bordered by cool glass and steel of Manhattan's cityscape in the distance.
The New York Earth Room is an interior sculpture by the artist Walter de Maria that has been installed in a loft at 141 Wooster Street since 1977. Go see!