A simple concept, nimbly executed by Minnesota Public Radio: Take vintage comedy routines, package them as streaming audio, and let the yuks begin. Excerpted from radio and concert recordings, highlights include Bob Newhart as a nervous driving instructor, Mike Nichols and Elaine May in a nagging-mother routine, and Bill Cosby explaining how he fought off a man-eating chicken heart. With Garrison Keillor exec-producing and Steve Martin hosting, it’s an institution of higher laughing. (