Clark: Worse? How could things get any worse? Take a look around you, Ellen. We're at the threshold of Hell.
In the scene where Clark is working on the lights the full moon is shown. This is December 14th according to the advent calendar. On December 24th when Santa's sleigh goes sailing over the moon, it is still full.
Clark Griswold in the attic watching old movies dressed in a woman's turban and gloves to keep warm is not only funny but a reference to the Norma Desmond character from "Sunset Blvd.", who watches her old films to remember her Hollywood glory days.