The Friday night shows here have been top secret for a while, but the folks at Vulcan Radio said we can tip off our readers. Vulcan Radio is a Web station that hosts live concerts on weekends in a warehouse somewhere in East Oakland. The mysterious to-do is dubbed Barbara’s Cocktails, and it features Bay Area bands like Persephone’s Bees, Tres Pistolas, and October Allied. There is no cover, the booze is free (yes, free) or BYO, and you have to be 21 to get in. It’s basically a private party, open to anyone who isn’t a nut or a thief or who is resourceful enough to find the secret location.