When Sam and Dean realize that Don Stark is a witch, too, Dean says, "It's full-on War of the Roses." He is referring to the movie "The war of the Roses" where a married couple, Michael Douglas and Kathleen Turner, star a couple that is involved in a vicious divorce battle.
Throughout the episode, Sam and Dean make references to "Bewitched". When they discover that Don Stark is also a witch they say that it is like someone switched Darrens. This is a reference to the casting of Darren on "Bewitched" switching from Dick York to Dick Sargent.