The lullaby Dwight briefly sings to Ryan is not made-up, but in fact a well-known German lullaby called "Schlaf, Kindlein, schlaf" ("Sleep, little child, sleep"). Rainn Wilson was taught this song by the script supervisor Veda Semarne, who learned it from her Austrian grandmother.
Michael orders a Midori sour, which is a similar drink to the one Josh and Jim joke about in The Convention (2006). Josh says "a shot of Midori, perhaps. Inside joke back in Stamford", to which Michael replies "I love inside jokes, I'd love to be a part of one someday".
Jim has Oscar speak to the cleaning crew to unlock the gate because Oscar speaks Spanish. In real life John Krasinski speaks Spanish fluently.
When Ryan is gaining access to the nightclub, he is heard off screen saying "Ryan Howard the baseball player, check again" - a reference to the baseball player he shares his name with.
After Ryan makes a confession to Michael about "his friend Troy's" drug problem, Michael suggests Ryan put a wire on him and flip him. Michael then says, "Been watching The Wire recently. I don't understand a word of it." Shortly thereafter, two actors from The Wire (2002) have made appearances on "The Office" - Amy Ryan (Holly Flax) who played Officer Beadie Russell on "The Wire" and Idris Elba (Charles Minor) who played Stringer Bell on "The Wire".