This has long been a "walking around the neighborhood with my headphones in" staple, got the perfect atmosphere for night walk with a chill in the air.
Spoiler alert. At the end of the movie, the Barbies hatch a plan...
They distract the Ken's by coyly listening to their monologues on film, golf, computers and music. The Ken with a record player mentions Malkmus by name as Barbie fawns over his knowledge. Very funny.