Figures from Adrian’s past return in a very witty and well-done 100th episode of “Monk” (8 p.m., USA). Eric McCormack (“Will & Grace”) guest stars as the smug host of “In Focus,” a tabloid TV news magazine that follows Monk as he tries to solve his 100th case, a series of murders involving aspiring actresses.

The fake show does a wonderful job with the pompous and absurd conventions of news magazines, most notably, the habit of filming re-enactments of grisly crimes in slow-motion black and white. From its Philip Glass-inspired music to bad Photoshop elements, the “In Focus” parody gets everything right. Make that wrong.

Many old faces resurface in interviews, including Sarah Silverman as Marci Maven, Monk’s most obsessive fan; Adrian’s older brother (John Turturro); and several of the killers that Monk has put behind bars, including Hal Tucker (Andy Richter), Joey Krenshaw (David Koechner) and Jimmy Belmont (Ricardo Chavira). Howie Mandel returns as cult leader Ralph Roberts.

The sight of actors playing characters who are supposed to be “real people” made nervous by a TV camera reminds us that “Monk” not only showcases good talent, it also respects a viewer’s intelligence. Along the way, it makes the point that “reality” television turns everybody into an actor and makes fakes of us all.

¢ In a rare show of unity for a good cause, three networks will broadcast “Stand Up to Cancer” (7 p.m., ABC, CBS, NBC), a fundraiser for medical research.

Hosts include network news anchors Brian Williams, Charles Gibson and Katie Couric. Celebrities include cancer survivors Lance Armstrong and Christina Applegate, as well as a long list of performers from “Idol”‘s David Cook to “Ugly Betty”‘s America Ferrera and “Christine” star Julia Louis-Dreyfus.

¢ A fairy tale in modern times, the six-part miniseries “Samurai Girl” (7 p.m. and 8 p.m., ABC Family, continuing on Saturday and Sunday nights) stars Jamie Chung as Heaven, a foundling child adopted by one of Japan’s wealthiest families. Fate – and ninjas – send Heaven on a quest to discover the truth about her family, her origins, and, of course, her destiny. Based on a series of young-adult novels, this should appeal to ‘tweens and teens who enjoy all that mystic martial arts malarky.

¢ “Sizzling Fall Preview” (5 p.m., E!) anticipates the new season of network television. CBS also airs a “Fall Preview” (8 p.m.).

Tonight’s other highlights

Note: Listings may vary because of sports coverage.

¢ Performers, including Keith Urban and Usher, celebrate the return of football season on “NFL Opening Kickoff 2008” (8 p.m., NBC).

¢ Michael Vick’s abused dogs face rehabilitation on “Dogtown” (8 p.m., National Geographic).

¢ Treadwell mourns a fox cub on “Grizzly Man Diaries” (8 p.m., Animal Planet).

¢ Season one ends with big decisions and a summer-ending clambake on “Swingtown” (9 p.m., CBS).

¢ “20/20” (9 p.m., ABC) looks at the dark side of foreign adoptions – families confronted by severely disturbed, violent and even dangerous children beyond their control.

¢ Roller derby is a mystery on “Psych” (9 p.m., USA).