"Get an elegant dose of seasonal cheer at the Holiday Champagne Bar at the Mandarin Oriental in Back Bay. Sip glasses (and bottles) of Louis Roederer, champagne cocktails, and light caviar bites. Open Fridays and Saturdays on December 6, 7, 13, 14, 20, and 21, 5 to 8 p.m. and New Year’s Eve, 5 to 8 p.m." - Celina Colby, Erika Adams