Taken from the National Lampoon Christmas Vacation movie.

(Noun) - Someone who gets possessed by the Christmas Spirit and enjoys it a little too much

(Verb) - its the act of getting way too into Christmas, including decorating your house in an obscenely obnoxious way or traveling out to the middle of no-where to cut down an oversized Christmas tree.
John realized he went Clark Griswold on his house when he could see the lights from across town.
by mildmanneredclarkkent December 1, 2009
Get the Clark Griswold mug.
When someone has the parks far back in a parking lot, even when there are plenty of spaces available closer; When one fails to realize that the person whom they are trying to yell for is right behind them; overabundance of christmas lights.
Dude! Why are you Clark Griswold-ing it?!?!?!?! There are plenty of spaces closer to the door!!

Well... Looks like the Smith's Clark Griswold-ed their house for Christmas again!!
by Just_Kidding December 1, 2012
Get the Clark Griswold-ing it mug.