The CW is the last of the broadcast networks to bring back returning series, although there will be stragglers from the others. Meanwhile, here’s what to watch and what to avoid on television this week:

Monday: “iHeartRadio Music Festival” 7 p.m., The CW: Acts ranging from Enrique Iglesias to Pitbull perform in highlights from the online radio outlet’s 2012 festival.

Tuesday: “Senatorial Debate” 7 p.m., ABC: Democrat Paul Sandler and Republican Ted Cruz duke it out, verbally.

“Heart of Dixie” 7 p.m., The CW: Season 2 kicks off tonight.

“Raising Hope” 7 p.m., Fox: Melanie Griffith appears in the third season opener as Sabrina’s mom. Melanie’s mom, Tippi Hedren, plays Sabrina’s grandmother (Melanie’s character’s mother). If my head explodes, this episode’s funeral won’t be the only one.

Wednesday: “Presidential Debate” 8 p.m., Broadcast and cable news networks, PBS: The first face-off between President Barack Obama and Mitt Romney takes place in Denver and focuses on domestic policy. Jim Lehrer referees — er, moderates.

“Supernatural” 8 p.m., The CW: Not into politics? Then watch Sam and Dean reunite in tonight’s eighth-season opener.

Thursday: “30 Rock” 7 p.m., NBC: For better or for worse? I’m guessing much, much worse. You’ve seen Jenna scheme and steam and you just know that her wedding planning is not going to be a picnic.

Friday: “Shark Tank” 7 p.m., ABC: I don’t know about you, but a spring-loaded laundry hamper just sounds like trouble. You might as well toss your socks into a T-shirt cannon.

“Fringe” 8 p.m., Fox: OK, Walter’s old Harvard lab was pretty grimy in 2011. I think they’re going to need one of those amber-cutting devices to get through the caked dust in 2036.

Saturday: “Winged Planet” 7 p.m., Discovery: Oh, so that’s how we stay up in the air.

“Austin City Limits” 7 p.m., PBS: Radiohead performs in the Season 38 premiere.

“Bedlam” 8 p.m., BBC America: She sees dead people. And she’s come to Bedlam Heights to find Jed as Season 2 begins.

Sunday: “America’s Funniest Home Videos” 6 p.m., ABC: You just know a season that begins with errant, stuck straws is going to be good, right? Right?

“The Cleveland Show” 6:30 p.m., Fox: Halloween high jinks launch Season 4.

“The Simpsons” 7 p.m., Fox: Time travel, a deal with the devil and the end of the world all figure into the program’s 23rd “Treehouse of Horror” installment.