Set in January 1967.
Megan Draper auditions for the Jules Feiffer play "Little Murders," which opened on Broadway in 1967 and only ran for seven performances. It was more successfully revived in 1969 Off-Broadway, with cast that included Linda Lavin, Fred Willard, and Vincent Gardenia.
Last episode of Dale, played by Mark Kelly. Dale was one of the original ad men from the pilot episode. He vanished after the first episode of season 2 until season 3, and then turns up here in season 5.