It’s a whole theme for New Year’s Eve at The Kennedy Center: Cheyenne Jackson…Music of the Mad Men Era. He’s a 30-something leading man on Broadway, a film, and television star (including 30-Rock) and a whole lot more. Then you are then invited to welcome 2013 in style after the concert, with dancing to the sparkling arrangements of D.C. jazz band Chaise Lounge in the Grand Foyer until 1 a.m. There’s a big balloon countdown at midnight. Free for all patrons with any December 31 evening performance ticket or Roof Terrace Restaurant receipt from that evening. So,the NSO, and Principal Pops Conductor Steven Reineke Mon., Dec. 31, 2012, 8:30 pm in the Kennedy Center Concert Hall.