* CSI: Crime Scene Investigation (9/8c CBS)
Nick, Greg and Hodges plan a special birthday outing for Henry (Jon Wellner), the lab's toxicologist, but their joy ride to obscure eatery Harry's Hog Hideout turns a bit more adventurous than they envisioned. At the rundown restaurant the guys uncover a body, a squirrelly raccoon, and some loco locals.
It's a family affair on tonight's episode when singer-actress Zooey Deschanel, Emily's younger sister, guest stars as Brennan's second cousin, Margaret. Margaret, who possesses a peculiar fascination with Ben Franklin, drops in out of the blue for Christmas, but since the distant relatives don't exactly hit it off, it wouldn't be surprising if Brennan turns to a "Poor Richard's" quote of her own: Fish and visitors smell in three days. Ryan O'Neal also guest stars as Brennan's father, Max.
Good ol' boy Bubba J may think he's got his drinking under control, but since it's really Jeff calling the shots, tonight's first-season finale finds our favorite pickled puppet trying to dry out with rehab expert Dr. Drew. Meanwhile, Achmed tries to bolster his ranks at a job fair, Peanut gets dating tips from a pick-up artist, and Walter apologizes to his wife for things he hasn't done - yet.
* 30 Rock (9:30/8:30c NBC)
It's Christmas at Rockefeller Center, and it might be Jack who receives the greatest gift of all. The tampering network exec fumbles around a new social-networking site, only to chance upon a former high-school flame (Julianne Moore). We then turn to Kenneth - the page who's all the rage - but there aren't many ho-ho-hos for him when he struggles to organize a holiday gift swap. In other holiday happenings, Liz sets out to buy a gift for the finicky Jack; and an aghast Jenna must share her yearly holiday solo performance.
Our sunny Philadelphians conclude their fifth season by doing one of the things they do best: drink to excess. It seems that they have been allowed to enter the City of Brotherly Love's flip-cup beer-drinking tournament (the Flipadelphia) after having been banned from it for 10 years. (One can only imagine why.) Unfortunately, their old rivals won't be competing. They have grown up. Guest stars include "Damages" murder victim Noah Bean and "Prison Break" alum Marshall Allman.