What’s On for Friday, Jan. 27 thru Sunday, Jan. 29: Celebrating legends with a Debbie Reynolds movie marathon on TCM, and The Mary Tyler Moore Show’s final season on SundanceTV. Plus: Tom Brokaw’s 50 years with NBC News

Debbie Reynolds Movie Marathon (Friday, starts at 6 am/5c, TCM): The irrepressible movie star, who passed away a month ago following the death of her daughter Carrie Fisher, gets the full Turner Movie Classics treatment, with 24 consecutive hours of her best-remembered movie. The centerpiece, naturally, is her breakout role alongside Gene Kelly and Donald O’Connor in the brilliant 1952 Singin’ in the Rain (6/5c) musical, followed by her Oscar-nominated performance as The Unsinkable Molly Brown (8/7c). If you stay up late, you can catch her as The Singing Nun (2:15 am/1:15c). On second thought …

The Mary Tyler Moore Show Marathon (Saturday, starts at 6 am/5c, SundanceTV): Want to turn your world on with one of the world’s most memorable smiles? Spend the day with Mary, Lou and the rest of the WJM crew as the entire 24-episode final season airs consecutively in a celebration of Mary Tyler Moore’s masterwork. It culminates in one of the great farewell episodes of all time, and a sight gag that will make you smile through your tears. (Not to be outdone, nostalgia channel MeTV will air six of the most beloved episodes in a three-hour Sunday block starting at 2 pm/1c, including the immortal classic “Chuckles Bites the Dust,” “The Dinner Party,” and two from the final season, “Lou Dates Mary” and the “The Last Show” finale.)

Tom Brokaw at NBC News: The First 50 Years (Sunday, 9/8c, NBC): And now for a salute to the career of a still-living legend, as newsman Tom Brokaw’s 50-year history with NBC is remembered with highlights from his reporting and anchoring career. Paying tribute in new conversations: luminaries including Oprah Winfrey, Bill Gates, David Letterman, Jon Stewart, Tom Hanks and Hamilton‘s Lin-Manuel Miranda.

Inside Weekend TV: Christina Ricci is troubled Southern belle and Jazz Age flapper Zelda Fitzgerald in Amazon’s Z: The Beginning of Everything (Friday), a series-long biopic dramatizing her tempestuous marriage to rising literary star F. Scott Fitzgerald (David Hoflin). … In the penultimate episode of the second season of The CW’s Crazy Ex-Girlfriend (Friday, 9/8c), Rebecca (Rachel Bloom) freaks out with only two weeks to plan a DIY wedding by herself. Among those she leans on: a delivery guy played by Seth Green, which makes us wonder what took him so long to show up on this twisted series. And just in case you thought Crazy had exhausted its obsession with bodily functions, guess again. … The great Lily Tomlin receives the Life Achievement Award at the 23^rd Annual Screen Actors Guild Awards (Sunday, 8/7c, TNT and TBS). Presenting the accolade: her 9 to 5 co-stars Dolly Parton and Jane Fonda, the Grace to her Frankie. … Arrr! Starz launches the fourth and final season of the swashbuckling Black Sails (Sunday, 9/8c) in the wake of a catastrophic battle, as the legend of “Long John Silver” grows.