The cop that pulls over Sam and Dean is wearing a 60's style police uniform. When they hid the cop car later, you can see the number of 54.. "Car 54, Where Are You?" was a sitcom in the 60' and starred Fred Gwynne and Al "Grandpa" Lewis. Both of whom were also in the Munsters
The trivia items below may give away important plot points.
The brothers confront a demon disguised as a police officer. Dean realizes the officer is a demon and kills him and subsequently the brothers have to hide the body and police car. The number of the car "54" is clearly shown. This is a reference to the old TV show Car 54, Where Are You? (1961).
Lilith's everyday birthday, with its candy meal is stylistically similar to one of the vignettes in the movie Twilight Zone (1983) and includes both dialogue and plot references. This movie's third segment, "It's a Good Life," was directed by Joe Dante. After one of the characters is caught trying to pass a note saying "HELP! Anthony's a Monster" much like the grandfather did at the mailbox, Anthony wishes him away unlike Lilith who breaks her grandfather's neck.