The "lullaby" that Castiel sings to baby Tanya is actually the theme song to the '80's TV show The Greatest American Hero (1981).
Crowley teases Kevin by calling him "Short Round", the name of the Indiana Jones' Asian kid sidekick in Indiana Jones and the Temple of Doom (1984).
When Castiel unbuttons his shirt in preparation for his date, Dean tells him, "That's far enough, Tony Manero". Tony Manero was the character John Travolta played in Saturday Night Fever (1977).
When Dean answers the phone in the mini mart he says, "This is Agent Lee Ermey." R. Lee Ermey is an actor most famous for his role as the savage Gunnery Sergent Hartman in Stanley Kubrick's Full Metal Jacket (1987).
Dean says, "I'll track down this Kevorkian wannabe." Dr. Jack Kevorkian -- often called Dr. Death -- is known for his role in the national debate over physician-assisted suicide for terminally-ill patients.