Marion Ross (“Happy Days”), Jim Belushi (“According to Jim”), Judd Hirsch (“Taxi”) and Joyce DeWitt (“Three’s Company”) appear on “ABC’s 50th Anniversary Blooper Celebration” (7 p.m., ABC). Let’s get this straight. A once proud network has chosen to celebrate a half-century of progress with a blooper show? That’s pathetic.

But what does ABC really have to celebrate? The “Idol”-driven rise of Fox has pushed ABC into fourth place. And on some nights, its fortunes sink even lower. And why not? What has ABC’s entertainment division created recently? “Regular Joe”? If you take away primetime sports, news and packaged reality gimmicks, ABC barely exists as a network anymore. For the week ending April 20, only three ABC shows ranked among the top 30 shows: “The Bachelor” (No. 23); “NYPD Blue” (No. 29) and the Easter night repeat of “The Ten Commandments” (No. 28). A 47- year-old movie, a 10-year-old cop show and “The Bachelor.” Ouch.

If you look down the list, the story gets sadder. ABC once had a hit called “The Practice” on Sunday nights. So it moved the show to Mondays, where it has all but disappeared. For reasons unclear, the network seems to want to smother the series. So, on the first Monday night of sweeps ABC will air the 2000 spoof adaptation of “Charlie’s Angels” (7 p.m., ABC). Hey, that was an ABC show. Back when it was a network.

• You’ve heard of Civil War re-enactors, now meet the Class War re-enactors. They’re the 21st-century stars of the historical reality series “Manor House” (7 p.m., PBS). They’ve agreed to live out the roles of a family of genteel tycoons and their servants and abide by the rules of the highly regimented class structure of Edwardian England.
• A talent hunt scours five cities for a vocal powerhouse with attitude to match on the new series “Born to Diva” (8 p.m., VH1). The show will culminate in the selection of a diva who will perform May 22.

Tonight’s other highlights

• Debra becomes a woman under the influence on “Everybody Loves Raymond” (9 p.m., CBS).
• Cruz enlists Bosco to hunt down her sister’s killer on the third-season finale of “Third Watch” (9 p.m., NBC).
• Masked men seek love on “Mr. Personality” (9 p.m., Fox).

Series notes

Shelly Berman guest stars as Arthur’s half brother on “King of Queens” (7 p.m., CBS) … Joe Rogan is host of “Fear Factor” (7 p.m., NBC) … Aisha is forced to confront her troubled father on “Boston Public” (7 p.m., Fox) … A romantic trap on “The Parkers” (7 p.m., UPN).

Late night

Ashton Kutcher and Jack Hanna appear on “Late Show with David Letterman” (10:35 p.m., CBS) … Jay Leno welcomes Hugh Jackman and Jimmy Buffett on “The Tonight Show” (10:35 p.m., NBC).

Martin Scorsese, Paget Brewster, Tony Bennett and k.d. lang appear on “Late Night with Conan O’Brien” (11:35 p.m., NBC) … Anna Paquin and Groove Armada are booked on “The Late, Late Show with Craig Kilborn” (11:37 p.m., CBS).