Wednesday

8 p.m. on NBC-4

The Sing-Off: It’s a mixed bag of music in this new episode as the five remaining groups unite for a performance of “With a Little Help From My Friends” before each group puts together a medley of songs by a single artist. Then judges Ben Folds, Shawn Stockman and Nicole Scherzinger decide what they’ll sing next, picking pieces from a variety of musical genres. Nick Lachey hosts.

Thursday

9 p.m. on ABC-7

Grey’s Anatomy: The staff of Seattle Grace Mercy West Hospital is still shaken by the horrifying shooting spree, so it’s a good thing a trauma counselor (guest star James Tupper) is on hand to assess each doctor’s readiness, as Derek (Patrick Dempsey) tries to take things too quickly by rushing back into surgery, and Cristina (Sandra Oh) buries herself in work in “With You I Am Born Again.”

Friday

8 p.m. on CBS-2

Yes, Virginia: After a playground bully tells her that Santa Claus does not exist, 8-year-old Virginia O’Hanlon (voice of Beatrice Miller) writes to the New York Sun, asking whether St. Nick is real. Her letter attracts the attention of curmudgeonly editor Francis Church (voice of Alfred Molina), who responds in print with one of the most famous holiday columns of all time.

Saturday

9 p.m. on NBC-4

WWE Tribute to the Troops: Bob Hope is gone, but his legacy of entertaining the troops lives on. Sherri Shepherd (“The View”) and Rima Fakih, the reigning Miss USA, join World Wrestling Entertainment stars and divas to entertain members of the U.S. military at Fort Hood, Texas, in this new hourlong special.

Sunday

8 p.m. on CBS-2

Survivor: Nicaragua: The 21st(!) edition of Mark Burnett’s combination of a competitive reality show and riveting psychodrama draws to a close with a two-hour special episode. Series host and producer Jeff Probst admits he had reservations about this season’s ”old versus young” premise initially, but adds, “It’s hard to second-guess (executive producer) Mark Burnett when he is right 99 percent of the time. ... We had such a great group of older people.”

Monday

8:30 p.m. on CBS-2

Rules of Engagement: Audrey (Megyn Price) contemplates quitting her job after realizing how miserable it makes her, while Allison (guest star Taryn Southern) tells Timmy (Adhir Kalyan) she wants to slow things down between them in “Play Ball.” Patrick Warburton, Oliver Hudson and David Spade also star.

Tuesday 9 p.m. on NBC-4

Saturday Night Live Presents: A Very Gilly Christmas: The good news: This collection of holiday-themed sketches includes such classics as Alec Baldwin’s “Schweddy Balls” skit with the NPR ladies (Molly Shannon, Ana Gasteyer), plus that unprintable Andy Samberg-Justin Timberlake duet about something in a box. The bad news: To get to those, you have to suffer through mind-numbing bits with Kristen Wiig’s irritating Gilly character. Does anyone outside of the “SNL” writers actually think those are funny?