One of the only things I enjoy about taking the subway these days is seeing the defaced ads on the L train. Whether it's random chance, high schoolers or street artists the result is always good.
This is one of my favorite bars in Manhattan. It has a courtyard in the middle and they only serve a large selection of Belgian beer. It's always dark with red lights so it's like a giant darkroom with everyone developing hangovers instead of film. The courtyard creates a front bar that is open on the weekends, so if you get cornered talking about architecture you can escape over to the front bar and watch people walk down 4th street.
My favorite neighborhood fancy chinese spot. Quality soup dumplings (it's obligatory to get an order). Mock eel (mushrooms), ants climbing a tree (noodles), salt & pepper fry (fresh daily), and mu shu duck are some of the go-tos. It's spicy and filling—worth a night of feasting.
You've heard about the reading room at the New York Public Library, haven't you? Then I need not go on. Just look at it. And you're allowed to hang around in there!