What to Watch Monday: The Alphas and Switched Finales, a Red John-athon and One Last Debate

On TV this Monday: Alphas and Switched at Birth close out their seasons, TNT catches you up on The Mentalist‘s hunt for Red John, RuPaul’s All Stars Drag Race saves the queens and the presidential candidates meet for their final debate. All told, here are nine programs to keep on your radar.

Noon-11 pm The Mentalist: The Hunt for Red John (TNT) | The cabler’s Mentalist marathon focuses on Jane’s nemesis: the elusive serial killer who offed his wife and daughter. The day-long run begins with the CBS series’ pilot and ends with the Season 4 finale “The Crimson Hat.”

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8 pm Alphas (Syfy) | Season 2 finale: Doctor Rosen is injured and out of his mind with grief, but it doesn’t stop him from seeking a final confrontation with Stanton Parish, who’s out to stage the definitive “flash” mob. An “interesting” interpretation of NYC’s famed Grand Central station guest-stars. (No word yet on a Season 3 renewal.)

8 pm Switched at Birth (ABC Family) | Season 1 (no really, it’s still just Season 1) finale: The trial concludes, Bay and Zarra take off in secret and Daphne’s relationship with Jeff is exposed. (Watch a sneak preview of the already renewed drama.)

8 pm Dancing With the Stars: All-Stars (ABC) | The remaining contestants explore the theme of guilty pleasures. (Whoa. Meta.)

8 pm The Voice (NBC) | The Battle Rounds continue. (Missed last week? Catch up with Michael Slezak’s recap.)

8 pm 90210 (The CW) | Naomi poses as a wealthy investor and lures Alec to her yacht, where he kisses her. Also, the girls throw Silver a baby-to-be shower — aka an irresponsible day full of all the stuff she won’t be able to do (such as drink and see her feet) once pregnant.

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9 pm Presidential Debate (All major networks) | President Barack Obama and former Massachusetts governor Mitt Romney engage in their final debate, which will focus on foreign policy. Face the Nation‘s Bob Schieffer moderates the event, held at Florida’s Lynn University.

9 pm Gossip Girl (The CW) | Chuck gets closer to finding out what Bart’s hiding, Dan’s first published serialized article causes a fervor and Blair and Serena make nice in order to make Sage happy. Fashionista Alexa Chung guest-stars.

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10 pm RuPaul’s All Stars Drag Race (Logo) | Premiere: Queens from past seasons of RuPaul’s Drag Race – including Nina Flowers, Jujubee and Tammie Brown – return for some wig-to-wig competition.

Which of the above is must-see for you? Also, hit Comments to offer your own tune-in suggestions.