“Margaret Cho: Beautiful” (10 p.m., Showtime) captures the star of “All American Girl” and “The Cho Show” in standup mode, examining the nature of beauty and the pressure on people to be and to feel good about their appearances. “I want everyone to feel beautiful and I want to do it with laughter,” says Cho. “Why not feel good about ourselves?”

• Vincent Pastore guest stars on an episode of “Chopping Block” (7 p.m., NBC) set in Manhattan’s Little Italy, where contestants must prepare lunch at a restaurant for tourists and regular patrons.

The “Sopranos” star has done a great job of keeping himself on camera, both in acting jobs and appearing as himself. Pastore’s credits include a recent “Apprentice,” season, “Celebrity Family Feud,” “Celebrity Fit Club,” “Iron Chef” and “I Love the ’90s” as well as “I Love the ’80s.”

Pastore’s frequency as a serial cameo star ranks right up there with Carnie Wilson, the singer/celebrity who has gone on to host a new version of “The Newlywed Game” on GSN. Wilson has appeared on “Gone Country” and the never-to-be-forgotten celebrity magic competition series “Celebracadabra.” She and Pastore both appeared on “Celebrity Fit Club” in 2006.

• Given the big buildup to his new job, Conan O’Brien’s tenure at “The Tonight Show” (11:05 p.m., NBC) has been pretty trouble-free. His past month has certainly been more controversy-free than rival David Letterman’s. In fact, the closest thing to a tempest on “Tonight” occurred on a show, repeating tonight, in which William Shatner mangles a Vulcan hand salute. Kobe Bryant and Incubus also appear.

• Jeff Foxworthy hosts “Are You Smarter Than a Fifth Grader?” (7 p.m., Fox). The quiz series gets into the summer swing with the appearance of hot-dog eating champ Joey Chestnut.

• A repeat presentation from 2008 “Nazi Scrapbooks from Hell” (8 p.m., National Geographic) looks at two photo collections that were not supposed to survive the Holocaust. One documents the arrival of Hungarian Jews in 1944 at the Aushwitz death camp.

Another collection is at once more innocuous and chilling. It recalls camp guards and personnel at moments of leisure — playing with dogs and enjoying a blueberry harvest. One expects that only monsters could work at such places, but these pictures reveal the camp workers to be ordinary folk. And that’s all the more horrifying.

Tonight’s other highlights

• “The Twilight Zone” (Sci Fi) marathon continues.

• Discovery offers 20 chances to catch “Deadliest Catch,” running continuously from 6 a.m. through 2 a.m. Saturday.

• Episodes of “Whale Wars” (6 p.m., Animal Planet) continue in marathon fashion through 5 a.m.

• Poltergeists infest the film lab on “Ghost Whisperer” (7 p.m., CBS).

• A home invader sticks to familiar territory on “Flashpoint” (8 p.m., CBS).

• Jack saves a gambling addict (Willie Garson) on the verge of a desperate act on “Mental” (8 p.m., Fox).

• A schemer (Vincent Price) tries to claim ownership of an entire state in the 1950 epic “The Baron of Arizona” (8:30 p.m., TCM), directed by Sam Fuller.

• A highway fatality does not add up on “Numb3rs” (9 p.m., CBS).