46. Danny Siegel
Showcase Episode: "Waldorf Stories"
Roger Sterling's second wife's idiot nephew, Danny stumbled into a gig at Sterling Cooper after he pitched a dumb idea that Don ended up accidentally using. Danny was always a cure for the common Mad Men episode, the butt of everyone's cruelest jokes — even Peggy came to enjoy having him and his pipe around. He was last seen making the Hollywood party scene. Played by Danny Strong, who went on to win an Emmy for writing Game Change and then co-created Empire, because the universe is one crazy place.