Okay, so this isn't in National Lampoon's Christmas Vacation, but it makes me think of the National Lampoon's series (the good ones, at least) and Christmas Vacation is one of two my go-to movies during the time of year. And apparently it is for the Walkmen too, since they decided to cover it as part of A.V. Club's Holiday Undercover Series.
The Walkmen cover "Holiday Road"
Wondering what the other movie is? The Ref with Denis Leary. "Do you know what this family needs? A mute." Classic!