Rattlemouth + Birdsongs of the Mesozoic

World-groove combo Rattlemouth is a spin-off from Orthotonics, a long-running art-punk band from Richmond, VA. Tonight it plays at 10pm, following an 8pm set by another legendary prog-rock group, Boston's Birdsongs of the Mesozoic, whose music forges a rare detente between punk power and contemporary-classical finesse.