Name your holiday game ADDICTION

Well folks it's that time of year again.  Christmas vacation for the kids and a lot of long weekends for you parents.  Which game is going to have your attention for the most part?  As long as we don't have another incident like last year we should be okay.  I know that personally I will be trying to get some more time in on Fallout 3 or even go back and continue past the four hour mark on GTA IV, heck who knows maybe even finish Bioshock.  I know GTA IV is supposed to be an awesome title, but for some reason, after buying it on opening day I became distracted by trying to finish my Seriously achievement before Gears 2 came out and only logged about 4 measily hours on it.  So...name your poison.