Queer ladies speed dating at the strand
Touted as the world's largest bookstore, you can literally get lost in this place.
If pushing marketers aren't your thing though, go on an off hour -- either super early, or later, when the crowds die down.
I can especially recommend the dog park later at night near the American Natural History Museum as a great place to meet single guys with big, sporty, friendly dogs, and the Carl Schurz small dog park as an excellent place to find lovely available ladies who like to cuddle tiny furballs. (OK, granted, sometimes the shows aren't particularly funny, but the booze helps with that). ) and they attract many creative, social, young people.