* American Idol (8/7c Fox)
It's all about inspiration this week on Idol. Last night, the seven still-standing singers performed a batch of inspiring tunes, a proper lead-in to tonight's uplifting "Idol Gives Back" episode, an initiative that raises funds for U.S. and global charities and brims with performances. Queen Latifah emcees the performance portion of the show from the Pasadena Civic Auditorium, where Alicia Keys (last night's mentor), Carrie Underwood, Black Eyed Peas, Annie Lennox, Elton John, Jeff Beck and Joss Stone, and Mary J. Blige take the stage. But on such a giving evening, something might be taken away: One of the Top 7 singers is slated to be eliminated.
* Mercy (8/7c NBC)
There's something about Mary Stuart Masterson, who resumes her guest-star arc in this character-driven hospital drama. Masterson's character, therapist Dr. Denise Cabe, comes to the fore when she continues treating nerve-jangled nurse and war vet Veronica, who's still coping with her post-traumatic stress disorder. Then there's Chloe, who desperately searches for an ER patient who may have a deadly affliction. Meanwhile, Sonia's role in her home-care patient's death comes into clearer focus.
* Accidentally on Purpose (8:30/7:30c CBS)
The first season closes with the conclusion of a two-parter, in which Billie goes into labor. In the previous episode, she lied about going into labor to get Zack out a speeding ticket. The officer insisted on escorting them to the hospital, where their real labors began - trying to escape without the officer seeing them. They did, with Davis' help, only to get stopped again... but this time, Billie isn't faking, and the real fun begins. Oh, except for Zack getting arrested and taken to the police station.
Steven Weber guest stars as an FBI agent who teams up with Mary and Marshall to persuade an informant to enter witness protection. The trio has its work cut out for them and must try to get through to the stubborn man, but Weber's character could face an even bigger challenge when he seems to take a liking to Mary. Stan, meanwhile, has his hands full as well with an ex-boxer witness who's suffering from dementia.
* P.O.V. (9/8c PBS)
Season 23 begins with Robert Kenner's provocative Food, Inc. The documentary examines the change in food production that's occurred over the past generation, when the corporatization of agriculture led to a few companies controlling almost everything. Here's one tidbit to chew on: Although a corn diet increases the risk of E.coli in cows, corn is what they're fed. As food-safety advocate Barbara Kowalcyk notes, "we're not being protected at a most basic level." And she should know: Her 2-year-old son died in 2001 from an E. coli infection.