Goldfinger is a long-running ladies' spot in Shinjuku-nichōme (but open to all, save for Saturdays). The bar has a lowbrow-chic decor designed to look like a '70s motel, a friendly vibe and fun events, like Friday-night karaoke. Drinks from ¥700; no cover unless there's an event.
On the third Saturday of every month, the bar hosts Tokyo's most popular lesbian party, also called Goldfinger, held at a larger venue. Check the homepage for details.