Across the street from one of the dim sum palaces of Chinatown -- the Studio for Southern California History. It's privately run, filled with books and films and ephemera about the history of our part of the state. (I'm a fan of this link to other history-related sites and sights.)
It's also a wee bit quirky. For example, an LA freeways pinball machine.
Located at 977 N. Hill Street in our fair city. Open Friday, Saturday and Sunday from noon to 8 pm, and by appointment.
Bring some quarters for pinball. Beat my score.