FROM THE SURFACE of the pool, the Minnesota Underwater Hockey Sport and Social Club looks like a pack of slender elephant seals. The match is in full heat, but the pool seems calm; no one shouts or blows a whistle. Except for the splash of fins, and the puffing spouts from the snorkeling gear, it is silent. Swimmers surface, keeping their faces underwater to watch the play, and breathe for a few minutes. Then they sink down... More >>>