The X Factor: Vocalists who made it through auditions head to Miami for boot camp in this new episode (8 p.m. Fox).
Guys With Kids: Marny and Gary (Tempestt Bledsoe, Anthony Anderson) have four sons, but Marny still yearns for a little girl, so she tries to talk her husband into trying again. Erinn Hayes, Zach Cregger, Jamie-Lynn Sigler and Jesse Bradford also star in this new episode (8:30 p.m. NBC).
Supernatural: In the season premiere, Dean (Jensen Ackles) is out of Purgatory and goes to see Sam (Jared Padalecki), who is glad to see his brother but finds it difficult to leave his new life. Osric Chau and Mark Sheppard also star (9 p.m. KTLA).
Life After Top Chef: This new unscripted series follows former "Top Chef" contestants Richard Blais in Atlanta, Jen Carroll in Philadelphia, Spike Mendelsohn in Washington, D.C., and Fabio Viviani in Los Angeles as they reach milestones in their personal lives and culinary careers — from opening their own restaurants to expanding franchises and establishing themselves as leaders in the food world (10 p.m. Bravo).
Paranormal Witness: This special 90-minute episode "The Abduction" brings together the key people involved in the most famous alleged alien abduction case in history, the reported 1975 abduction and reappearance of Arizona logger Travis Walton, whose five-day experience inspired the film "Fire in the Sky" (10 p.m. Syfy).
Presidential debate: The first of three presidential candidates' discussion of issues takes place at the University of Denver. Jim Lehrer moderates (6 p.m. CBS; NBC; ABC; CNBCKCAL; Fox; MyNet; KOCE; CNN; CSPN; Fox News; Fox Business; MSNBC).