Final cast listing wherein Kaley Cuoco is credited as Kaley Cuoco-Sweeting, following the announcement of her divorce from Ryan Sweeting.
This was the second episode, set after the day of the Wedding, of the series to use Penny's new last name - Hofstadter. Her maiden name is still unknown at this point in the series.
Melissa Tang, who plays Mandy Chow in this episode, goes on to star as Ms Fenley in Young Sheldon (2017) - episode 1.1, Pilot (2017).
When Sheldon tells Amy that his 'compulsive knocking ritual' is a charming eccentricity which she no longer gets to enjoy as they are no longer 'friends with benefits' proves that he has still not yet grasped the concept of friends with benefits which he sought to grasp in The Vegas Renormalization (2009) (Season 2 Episode 21)
Sheldon uses the split of Czechoslovakia as an analogy to his unfriendly split from Amy. However, Czechoslovakia was created peacefully in the wake of WWI, not through conquest, and the split into the Czech and Slovak Republics in 1993 after the fall of communism was done with mutual agreement, not through an independence struggle by one of the countries.