By day they're a bunch of San Francisco's hottest product designers. By night they're a guerrilla band of concept hackers.
Faces are expectant or bemused.
Visitors, jockeying for position, wait their turn to stick their heads through the opening, and emerge a minute later, laughing, nodding sagely, or looking just as flummoxed as they did before. At times it can be provocative. The blond Russian sticks her head into the hole. Inside the hole is a computer screen suspended below a shallow vat of bubbling liquid. The woman looks at the vial warily, placing it with care into her Prada bag, as the next person steps up to the machine.