It's a pivotal weekend as the Winter Olympics and "Downton Abbey" wind down, NBC hopes to bolster new sitcoms with the Sochi Games, and competing programmers roll out new fare. The highlights:

The big local story is the Daytona 500. Fox's coverage starts at 1 p.m. Sunday. Richard Petty supplied drama by deriding Danica Patrick's abilities. Here's hoping it's a great race.

NBC says goodbye to Sochi with the Closing Ceremony at 8:30 p.m. Sunday. The network will offer the documentary "Nancy & Tonya" at 7 p.m. Sunday; Mary Carillo looks back at the strange saga of figure skaters Nancy Kerrigan and Tonya Harding. Friday prime time will feature the women's slalom, and Saturday offers the men's slalom.

NBC will preview two sitcoms after the Games. The more appealing is "About a Boy,"  which starts at 11:07 p.m. Saturday. The show is based on the Nick Hornby novel and the Hugh Grant movie. Will (David Walton), a self-absorbed bachelor, befriends a quirky neighbor boy, Marcus (Benjamin Stockham), and the results are charming.

“Growing Up Fisher” is a pleasant but wispy NBC sitcom that previews at 10:38 p.m. Sunday. The show focuses on a loving father (J.K. Simmons) who is a blind lawyer. Mom (Jenna Elfman) refuses to grow up. Their divorce throws the two kids a bit, but the sitcom is just so slight.

PBS' "Downton Abbey" concludes its fourth season with two hours at 9 p.m. Sunday. The British drama takes the opulence to a new level with a visit to the palace. Shirley MacLaine returns as Lady Cora's mother, and Paul Giamatti debuts as Cora's mysterious brother. The revelation: Nothing conclusive happens, and the whole season has been a bridge to next season. Still, the acting has been exceptional, and the scenes between MacLaine and Maggie Smith have the old zing.

"The Walking Dead" is on a roll after last weekend's stunning episode. The latest episode, called "Claimed," premieres at 9 p.m. Sunday on AMC. The channel provides this preview: "Just when Rick thinks he's going to be able to relax, he's faced with multiple immediate threats. Other members of the group deal with their past." "Talking Dead," at 10 p.m. Sunday, welcomes Mindy Kaling and "Walking Dead" star Michael Cudlitz, who plays Abraham Ford. 

"The Amazing Race" brings back 11 memorable teams for an all-stars contest at 8 p.m. Sunday on CBS. Those teams include cowboy brothers Cord and Jet, father-son cancer survivors Dave & Connor and newlyweds Brendon & Rachel. But the addition of Rachel from "Big Brother" may send some scurrying to other channels.

CBS' "60 Minutes" talks to actor Liam Neeson, who talks about his career and his late wife, actress Natasha Richardson. The Anderson Cooper chat airs at 7 p.m. Sunday.

TCM continues its 31 Days of Oscar festival. On Saturday, the channel will present the five nominees for best picture of 1948. The first film, "The Red Shoes," screens at 8 p.m. and remains one of the most visually stunning achievements in film history. "Hamlet" won the contest, brought Laurence Olivier the best-actor prize and starts at 10:30 p.m. The other three nominees were "The Snake Pit" with Olivia de Havilland at 1:30 a.m. Sunday, "The Treasure of the Sierra Madre" with Humphrey Bogart at 3:30 a.m. Sunday and "Johnny Belinda" with Jane Wyman at 5:45 a.m. Sunday. Wyman won best actress for her touching performance and gave one of the best acceptance speeches. This year's nominees should go back and study it.