I love Grand Central Terminal. Aside from being the largest train station in the world, and a major NYC icon it's a giant mixing bowl for the denizens of NY. Every time I pass through there I get that "I love NY" feeling. I know it's cheesy but it's true.
At right, is a shot from this evening. I focused on the stationary businessman and waited for the moment when plenty of people would enter the frame. A long exposure (1/3 second) gave the bustle effect I envisioned.