It’s a cold, dark night, and I’m looking for a speakeasy that should be next door to Marvin. I’m not quite sure what to do. I spy a set of ringers, with a small label next to one: The Gibson. I press it. A door opens, and the bouncer quickly waves me in. He checks ID with the low light from his cell phone; as he explains, the phone is dimmer, all the better for…