Fridge Brilliance: The incredibly-senile Aunt Bethany brings "presents" note (actually, her cat and a Jell-O mold) wrapped in "HAPPY BIRTHDAY" paper. Christmas is Jesus' birthday.
Fridge Logic: The two kids have their own rooms. Russ has a bunk bed. So why are the two kids sleeping in the guest room while one set of grandparents sleeps in Russ's room? Are the grandparents not getting along or something?
It's mentioned by Clark and Ellen earlier that their parents DO NOT like each other hence why each pair of grandparents has their own room. The first scene with the grandparents shows them arguing with each other.
I believe the previous Troper meant aren't each set of grandparents (Clark's parents Clark Sr. and Nora and Ellen's parents Art and Frances) getting along. If they were, it'd make more sense for Grandma and Grandpa Whichever to share the guest room (and guest bed), Grandpa and Grandma Whoever to share Audrey's room and have Russ and Audrey use Russ's bunk beds, rather than having Russ and Audrey share the bed in guest room.
When Clark is trapped in the attic, he accidentally punches a hole through the floor into Russ's room. Why doesn't he just climb out through the hole he just made? It's not like he could make it much worse.
I have ALWAYS wondered this.
It is possible that he couldn't fit between the ceiling and the bed.
He made the hole, saw the projector while he was standing there, then decided to check out some old family movies before he left. Unless I'm forgetting the series of events that seems most likely. Better answer: Rule of Funny. Also explains why the bed was about 6 inches from the ceiling.
How does Cousin Eddie know where to go in order to abduct Clark's boss? Clark simply mentions "Melody Lane" and "my boss," and Eddie comes back with the right guy. Even assuming that Melody Lane is a short street (which is a fair assumption, as it is made out to be an exclusive address), did Eddie go house to house? Does Eddie even know his kidnapping target's name? For that matter, the SWAT team zeroes in on Clark's house remarkably quickly, but admittedly Eddie's RV is an easily identified vehicle.
Clark mentioned his boss's full name (Frank Shirley) at the start of his now-famous rant. Eddie could've looked it up in a phone book or it's possible the Shirleys had their name on a mailbox or something. Shirley isn't that common a name, especially two on the same street.
Fridge Horror: Clark's not going to be able to afford that pool he wanted. His Christmas lights consumed so much power that they caused a blackout across town and another generator needed to be turned on at the plant. You can even see the electric meter start rapidly spinning after the lights turn on the first time. When the electric bill comes in, he can say goodbye to his Christmas bonus.