21 Grand was a performing arts space located at 416 25th St near God's Gym. The space was open from 2005-2011 when they shut after a "cease and desist cabaret activity" order from the City Administrator1

Check out the old yelp reviews.

References

1.  Gazdowicz, Anna. "Experimental Oakland art space, 21 Grand, served with ‘cease and desist’." The Bay Bridged: Oct 10, 2010.

Hix, Lisa, Oakland Art Gallery, Experimental Music Space, 21 Grand Set to Close, KQED Arts Blog, November 23, 2010

21Grand.org on the Wayback Machine