Who says the past is not prologue? A popular female “Today” show host best known for morning conversation is given a much publicized opportunity to host a network news broadcast. The decision is hailed and hyped as a breakthrough for women, a crash through the glass ceiling, a revolution in news. But the results are less than stellar and audiences don’t exactly swoon.

It sounds like the Katie Couric story, circa 2006. But 30 years ago, Barbara Walters left “Today” to join ABC News in 1976 as co-anchor (with Harry Reasoner) of its nightly news. While her anchor stint didn’t last, she would go on to “20/20,” “The View” and to host a gazillion prime-time interview specials. Tonight and tomorrow night, Walters looks back on “Barbara Walters: 30 Mistakes in 30 Years” (9 p.m., ABC).

Don’t go looking for great historical moments here. The accent is on the silly questions, the gaffes, goofs and embarrassing moments that Walters and many of her viewers cannot forget. The two-night, two-hour countdown includes an infamous moment when Walters asked actress Katharine Hepburn what kind of tree she would like to be. There’s also the time Demi Moore showed Walters how to dance like a stripper, the show when Walters asked a panel of heartthrobs about how they lost their virginity and the moment when she mistook Arnold Schwarzenegger for another celebrity.

“30 Mistakes” is filled with self-deprecating comments. But Walter’s ability to make fun of herself stems from a career marked by her ability to always get the big-name interview. “Mistakes” includes moments with Al Pacino, Will Ferrell, Jim Carrey, Jimmy Stewart, Lucille Ball, Patrick Dempsey, Jamie Foxx, George Clooney, Teri Hatcher, Brad Pitt, Halle Berry, Jerry Seinfeld, Ronald Reagan, David Letterman and countless others.

It remains to be seen if Katie Couric’s anchor job pans out. But if she gets to host a retrospective like this in the year 2036, she won’t have too much to complain about.

Tonight’s other highlights

¢ A former victim (Christian Slater) wants to teach Randy and Earl to be Earth-friendly on “My Name Is Earl” (7 p.m., NBC).

¢ The Mode staff celebrates Thanksgiving together and alone on “Ugly Betty” (7 p.m., ABC). Martha Stewart cameos.

¢ The merger of the Scranton and Stamford branches brings mixed emotions on “The Office” (7:35 p.m., NBC).

¢ Identical twins share a grim anniversary on “CSI” (8 p.m., CBS).

¢ George’s family descends on the hospital on “Grey’s Anatomy” (8 p.m., ABC).

¢ The true crime documentary series “The First 48” (8 p.m., A&E) will continue its fourth season with six original episodes.

¢ Forced to make product placements, Liz integrates Jack’s “acting” into the show on “30 Rock” (8:20 p.m., NBC).

¢ A hit-and-run “accident” may have had a racial motivation on “Shark” (9 p.m., CBS).

¢ A mystery ailment leaves little time for deliberation on “ER” (9 p.m., NBC).