NBC fights "Survivor"-mania with two solid hours of sweeps-worthy stunt-casting. Ellen DeGeneres has a guest spot on "Will and Grace" (8 p.m., NBC) as a crafty nun involved in a hasty used-car deal with Grace. Anyone whose memory goes back three seasons will recall how Ellen courted controversy on "Ellen" by coming out of the closet and generally making her show more about being gay than being funny. "Will and Grace" has managed to do both, so expect some inside jokes.
Susan Sarandon has been exercising her funny bone of late. The Oscar-winning actress, known for her serious roles ("Dead Man Walking") and outspoken politics, can be a cut-up when she wants to. Fresh from a stint on "MadTV," Sarandon appears on "Friends" (7 p.m., NBC) as Joey's soap opera castmate. Joey inadvertently informs her of her character's demise, sparking a major fight that eventually leads to an unlikely fling. "Just Shoot Me" (8:30 p.m., NBC) features a cameo by actress Pamela Anderson.
Get ready for a new catch phrase. NBC has commissioned 13 episodes of the BBC game show "The Weakest Link" as a mid-season replacement. The show is a smash in England, where viewers have taken to the show's brutally dismissive hostess Anne Robinson. Robinson, who is also a newspaper columnist and BBC news reporter, will appear on the U.S. version of "Link." Her signature tag line, "You are the weakest link, good-bye!" has become a national phenomenon. You heard it here first.
Fox meets fiction with "Conspiracy Theory: Did We Land on the Moon?" (8 p.m., Fox). The notion that the Apollo project was a government fraud and that the televised landings were faked in some secret studio has been circulating for three decades now. "Conspiracy" lends documentary credence to skeptics who question the validity of photos taken on the moon. Why, they wonder, are there no stars in the night sky? Where is the evidence of a blast crater beneath the lunar landing vehicle? There are also mysterious shadows in some Apollo-era photos that these astro-doubters believe could have come only from mechanical lighting.
Tonight's other highlights
Having been AWOL for most of the February sweeps, "The Gilmore Girls" (7 p.m., WB) returns as Lorelei and Rory attend a Bangles concert.
An inside look at the QVC retail empire on "Behind Closed Doors with Joan Lunden" (8 p.m., A&E).
Another look at the Boston Strangler case on "48 Hours" (9 p.m., CBS). Postponed from an earlier date.
Greene faces a critical peer review, and Carter tries to save an infant whose parents refused a measles vaccine on "ER" (9 p.m., NBC).
Performances by Eric Clapton, Aretha Franklin, Bono, Tina Turner and, of course, a glance back at Milli Vanilli on "Greatest Rock and Roll TV Moments: The Grammys" (9 p.m., VH1).
Jessica Lange stars in "Sweet Dreams" (8 p.m., AMC), the 1985 musical biography of country singer Patsy Cline.
Another torch is extinguished on "Survivor" (7 p.m., CBS) ... Pet projects on "The World's Most Incredible Animal Rescues 3" (7 p.m., Fox) ... On back-to-back episodes of "Whose Line is it Anyway?" (ABC), superheroes (7 p.m.) and newscasters (7:30 p.m.) ... Wrestling on "WWF Smackdown" (7 p.m., UPN).
Conan O'Brien interviews members of the cast on "Friends Outtakes" (7:40 p.m., NBC).