Sid Caesar, the prodigiously talented pioneer of TV comedy who paired with Imogene Coca in sketches that became classics and who inspired a generation of famous writers, died Wednesday. He was 91. Family spokesman Eddy Friedfeld said Caesar, who also played Coach Calhoun in the 1978 movie "Grease," died at his home in the Los Angeles area after a brief illness. "He had not been well for a while.