The Black Cat nightclub in D.C. is also owned by Dave Grohl, former drummer for Nirvana and lead vocalist of the Foo Fighters. As musically unexciting as that would probably be for many of the patrons of the club (as it does, as was mentioned, do mostly indie shows), it is a bit interesting for celebrity contact value. The Foo Fighters do surprise shows there from time to time without giving them much announcement, and my ex was once lucky enough to get into one.

They are also now moving into a bigger building, the last I'd heard.

Ourboros asked me how long ago the Black Cat moved, and what its current location would be.
The Black Cat is now located at 1811 14th St. NW. I do not know when it moved (information welcome).

(Update)
Saturday is usually "MOUSETRAP: DC'S BRIT-POP DANCE NIGHT" or some other dance occasion. The Black Cat features a front stage as well as a back stage, the former being used for the big acts (that is, as big as indie shows get), the backstage usually used for smaller acts like local DJs and trance/rave/electronic stuff.