When Ms Draper reads tarot for Don, the cards show a betrayal in his past, hope and travel in his present and conflict and swift change in his future.
Peggy's Popsicle design campaign is an allusion to many Catholic images of the Virgin Mary, complete with the orange circle of the Popsicle logo serving as a halo for the mother. It follows up on Peggy's earlier comment in the episode that the Catholic Church knows how to sell things.
This episode's title takes its name from the piece that Anna Draper's young piano student is practicing when Don enters Anna's house: "In the Hall of the Mountain King," one of the pieces of music that Edvard Grieg originally wrote for Henrik Ibsen's 1876 play Peer Gynt.
At one point, a clip from Robert Wise's classic The Day the Earth Stood Still (1951) is playing on TV. In 2008, Jon Hamm starred in the Scott Derrickson remake.
The poem Roger recites to Alice Cooper are the first few lines of "Buckingham Palace" by A.A. Milne, first published in 1924 in a collection of poems titled "When We Were Very Young". The poem having significance to Roger and Alice makes sense given that the Coopers helped raise Roger (his comment "Best babysitter in the world." alludes to this) who would have been around 8 at the time of the poems release, having been born in 1916.