Sam calls Dean "Hef" when he wishes there was demonic activity in South Beach, referring to Hugh Hefner, founder of Playboy.
The establishing aerial shot of the Impala traveling through green fields dotted with livestock was also used in Skin (2005).
When Dean and Bobby are crossing the street outside the bar, at the end of the episode, you can see that it is the same street used in Eureka (2006) outside Jack Carter's sheriff's office.
"Sin City" is a song by AC/DC.
Quid pro quo is Latin for "this for that".