This season, Jessica Pare, as Megan Draper, has delivered some of the best moments in this or any season of Mad Men. She sang seductively to husband Don, in French, at a party that left him mortified and angry. When he was angered, again, by her dislike of the orange sherbet at Howard Johnson’s, she sarcastically shoveled spoonfuls of it it into her mouth like Harold defiantly ate his beets in Harold and Maude. Then, last week, after Don and company talked about hiring a group that sound