It looked like a graduation. On a Saturday afternoon, a crowd of people gathered around a small stage set up on the lawn in front of the Martin van Buren School, a sturdy Colonial Revival building in Kinderhook, New York. But rather than students in caps and gowns, a small parade of people beating out pseudo-African rhythms on hand drums proceeded up onto the stage. Next came a group of writhing dancers in gold masks and neon fur suits, and, finally, duos of performers inside colorful horse costumes. The audience, a mix of locals and a Manhattan art crowd who made the two-hour journey up the Hudson River, applauded the performance, which was organized by Chicago artist Nick Cave. Off to one side, art dealer Jack Shainman was beaming.