The song recorded by artists of the era including Mae Questel, Bob Crosby, and Tommy Dorsey, as well as decades later by Maria Muldaur.

Her father Émile (Ronald Guttman) and mother Marie (Julia Ormond), visiting from Montreal, argue in French.

Megan goes to check on her and, finding her mother asleep with a burning cigarette still in hand, sadly takes the flammable object away and leaves her alone to slumber.

Roger (John Slattery) and his ex-wife Mona (Talia Balsam) meet, and he tells her about how his recent LSD experience has changed his life.

The next day, Megan approaches Don with an idea for the Heinz campaign: a mother serving her child beans in various historical contexts, from caveman times through to the future.

They discuss different tag lines, and an excited Don tells Stan Rizzo (Jay R. Ferguson) and Michael Ginsberg (Ben Feldman) about the idea.

Abe Drexler (Charlie Hofheimer) calls Peggy (Elisabeth Moss) and insists on meeting her for dinner.

She tells Peggy that Abe is just using her as practice before he decides to marry and have a family with another woman in the future, and snidely advises her to just "get a cat" if she's lonely.

At the ACS dinner, Pete Campbell (Vincent Kartheiser) introduces Don and Megan to Ed Baxter (Ray Wise), Ken’s father-in-law.

Roger shows a genuine side when he spends the night with Sally on his arm, telling her about the event's attendees; Marie watches him from across the room.

Meanwhile, Émile tells Megan she has changed, that her marriage to Don has ultimately allowed her to take a shortcut in life instead of working for it, reminding her of her acting dreams she was once so driven about.

Back in the showroom, Ed tells Don the companies at the event love his talent and will shower him with awards but, because of the letter he wrote against Lucky Strike, will never hire him.

It is also, unfortunately, the last moment in this terrific episode where the rug is pulled out from under someone and they respond remotely that well ... [the episode's] proper conclusion is that beautiful shot of Megan's parents, Megan, Don and Sally sitting around that fancy table, some combination of disappointment, pain, betrayal and disgust washing over all their faces.

It was a nuanced play on generations that also—separately—was funny, sexy and had a very intriguing idea dropped so casually into the mix [that companies don't want to work with Don] it could easily have gone unnoticed.

"[5] Time magazine writer Nate Rawlings liked the episode's three solid plot lines for Peggy, Megan and Sally.

Yet as bad as things seem for ... Megan, Sally's venture into the adult world could charitably be called a disappointment (traumatic experience is more like it).

"[6] "At the Codfish Ball" was nominated for the Primetime Emmy Award for Outstanding Art Direction for a Single-Camera Series.