Mark Kelly, Gabrielle Giffords, Diane Sawyer Mark Kelly, Gabrielle Giffords, Diane Sawyer

This week, it's all about Regis Philbin. The irrepressible broadcasting legend, who holds a Guinness World Record for most hours spent in front of a TV camera, will finally give it a rest at the end of this week, as he steps away from Live! With Regis and Kelly (check local listings) after nearly 25 years in national syndication and many years before that in a variety of jobs, including as Joey Bishop's late-night sidekick in the late '60s.

His time on Live! cemented his popularity and his ubiquity, during which time he also launched Who Wants To Be a Millionaire on ABC to massive ratings (before the network burned it out). As Live! counts down to his Friday farewell show, the celebration will include visits by famous guests and friends, including David Letterman on Wednesday and his former co-host Kathie Lee Gifford on Thursday. On today's lineup: Jimmy Fallon and Don Rickles. There will also be surprise musical guests and themed retrospectives of his 28 years in the Live! hot seat. But if you think you've seen the last of this guy, you don't know Reege.

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Shifting to prime time, the big event is an ABC News prime-time exclusive: Diane Sawyer's sit-down (10/9c) with Rep.

Gabrielle Giffords and her husband, Space Shuttle Commander Mark Kelly, to discuss Giffords' remarkable ongoing recovery and rehabilitation after the near-fatal shooting in Tucson last winter that left six others dead.Signing the guest-star book: Rescue Me's John Scurti, last seen covering his friends in ashes and becoming Tommy's new ghost companion in the series finale, checks in on Fox's House (9/8c) as a patient convinced he has diabetes. ... And as Alan tries to recover from last week's mental breakdown on CBS' Two and a Half Men (9/8c), Gary Busey makes a special appearance, we're presuming in the mental ward. Run, Alan, run!So what else is on? ... Have hankies ready as you watch Animal Planet's Saved (8/7c), a new six-part docu-series about the therapeutic effect animals can have on people when they need a lift the most. In the opener, a stray war puppy from Iraq brings solace to the fiancée and parents of a soldier killed in the war. ... On CBS' How I Met Your Mother (8/7c), Barney and Robin try to keep last week's impulsive kiss from their respective current squeezes. Why bother? If it gets the mirthless Kevin (Kal Penn) and Nora (Nazanin Boniadi) off the show faster, someone please spill. ... It's been a while since The CW's Gossip Girl (8/7c) has been what you might call trendy, but this week the gang attends the ultra-hip immersive theater experience "Sleep No More" (a true New York phenom), and you never know what will happen when everyone dons masks.

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