Chestnuts roasting on an open-fire? Anything but: Nothing dated at this Dec. 26 concert, a save-the-date, circle-the-calendar event for classic standards from the "The Great American Songbook," fired-up by a pair of personable and protean performing pianists. Singular sensation? Double-up on the chorus line of hosannas as composer Marvin Hamlisch and crooner Michael Feinstein do a duo-piano engagement at Verizon...