Ticket sales at the Metropolitan Opera haven’t been great in recent years during the weeks following the Christmas and New Year’s holidays. So the Met has announced that it will be taking a two-week break in the middle of its season, beginning in January 2004. “This will be the first midseason break since the Met began in 1883,” and it may not be the only change the company makes to its schedule. Executive director Joseph Volpe says that the Met is also considering replacing its Monday night performances with Sunday matinees.