When the demons come for Lisa and Ben, Ben is reading "Cthulhu Tales" (2008), a collection of Lovecraftian comic book stories.
As Bobby leaves Judah's you can see the video game "Cthulhu Saves the World" being played in the background.
Balthazar asks Castiel if he is "in flagrante with the King of Hades". "In flagrante" is a term used to describe when someone is in the act of wrongdoing, and is often used to describe sexual misconduct.
This episode's title, "Let It Bleed" is also the title of a hit song by The Rolling Stones; yet another classic rock nod.