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 Administrator. 1
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