The song played at the end of the episode is "Shake It Off" by Taylor Swift. Jared Padalecki, Jensen Ackles, Misha Collins, and many other former cast members recently teamed up with The Hillywood Show of YouTube to do a Supernatural Parody video of this song called "Mark of Cain."
Dylan Everett, the actor who played 14 year old Dean, was 20 years old when the episode was filmed.
Dean asks Tina what JP's problem was, she says, "What wasn't? You're in here getting stunned while the sun's still up, your life's a regular Charlie Foxtrot." Charlie Foxtrot is military slang for a disaster.
The actor who plays young Dean, Dylan Everett's birthday is January 24th - the same as Dean's.
In one scene, a cuckoo clock can be heard chiming the hour. Cuckoo clocks are native to the Black Forest region of Germany, whence the original tale of Hansel and Gretel comes.