Guest Stars

SERIES Who Do You Think You Are? "Sex and the City's" Kim Cattrall is featured in this new installment (8 p.m. NBC). Supernatural: Sam and Dean (Jared Padalecki, Jensen Ackles) find themselves starring on a TV show in an alternate universe in this new episode (9 p.m. KTLA). Blue Bloods: There's murder most foul at a debutante ball on a new episode of the police drama (10 p.m. CBS). Onion News Network: A cyber attack on the U.S. is the latest faux crisis covered on the news-spoofing series (10 p.m. IFC)

Kristian Hoffman doesn't step out much to play his own music, being a much-in-demand bandleader and collaborator with the likes of Rufus Wainwright, Ann Magnuson, Lydia Lunch, Klaus Nomi, Dave Davies and others. Once part of L.A. punk band the Mumps, Hoffman is one of L.A.'s great musical raconteurs and has had his hands in an eclectic grab bag of projects since the 1970s. But Friday night, the local treasure is moving to center stage to debut his new album, "FOP," a 17-song collection he describes as "orchestrated baroque glam psych," at the Steve Allen Theater.

His hot young company just surpassed 500 million users. He's about to be portrayed in a major Hollywood film. Yet nothing says you've hit the big time like being asked to voice yourself on "The Simpsons." Mark Zuckerberg, the 26-year-old phenom behind the world's most popular social networking site Facebook, will play himself as a guest voice on the iconic Fox television show this fall. In the episode, "Loan-A Lisa," Lisa decides to help fund Nelson's new bike company.

There's a meta moment coming in Monday night's episode of "The Secret Life of the American Teenager" where 19-year-old Bristol Palin talks about being the mother of a toddler. The brief guest appearance came naturally — the acting part, well, that's another matter — because it mirrors her own life. "It was right up my alley," said Palin, daughter of former Alaska Gov. Sarah Palin. "I was pregnant the same time as the character, Amy, on the show, so I kind of felt like we went through the experience together."

As Disney Channel prepared to launch the cartoon series "Phineas and Ferb," one top company executive thought the hard, geometric shapes of the characters' heads represented too radical a departure from Disney's round-faced animation tradition. But talk of forcing the creators to soften the edges of Phineas' isosceles dome to make him and the other angular characters less jarring was quelled. "I said 'no,' " said Disney Channel Entertainment President Gary Marsh. "This is what I love about this show.