STRANGE THAT IT'S BEEN years since I last saw live performance. But everyone was exclaiming this now-familiar platitude as they busily embraced on the sidewalk at the intersection of Rivington and Orchard the past October, during the collective reunion which took as its backdrop and pretext Kevin Beasley’s The Sound of Morning. The first of eight commissions realized for this year’s Performa Biennial, the performance began almost unnoticeably. One of Beasley’s collaborators flung a deflated basketball into the air; another began methodically disassembling a black metal barrier that had been