New York Public Library, Jefferson Market Branch

Though the city's made up of five boroughs, it has just three public library systems. The largest—the NYPL—runs all libraries in Manhattan, Staten Island and the Bronx. Hours at the branches vary wildly, but all have a dedicated section of children's books, and many a separate room for the use of kids up to fifth grade. Storytimes, craft and cultural projects, and poetry writing workshops are just some of the offerings on tap; check the website (nypl.org) for detailed information on each branch.