The Ellen DeGeneres Show
(3 p.m., NBC10) - Colin Farrell; Diddy; Janelle Monae; YouTube sensation Greyson Michael Chance.
The Oprah Winfrey Show (4 p.m., 6ABC) - Four women say they were child brides in the USA.
American Idol (8 p.m., Fox29) - In the season finale, the top 12 finalists reunite for the last time before host Ryan Seacrest reveals the winner.
Criminal Minds (9 p.m., CBS3) - May is network sweeps month, but is it also Mass Murderer Month on CBS? It looks that way, as Rossi and Hotchner (Joe Mantegna, Thomas Gibson) and the rest of the team track a serial killer (guest star Tim Curry) in Los Angeles who targets families, slaughtering all the members except one witness, who's left to be haunted by the experience. Eric Close and Robert Davi also guest-star in "Our Darkest Hour," the season finale.
Law & Order: Special Victims Unit (10 p.m., NBC10) - When a disabled woman (Lisa Arrindell Anderson) is beaten and raped, she is left unable to speak, but Benson and Stabler (Mariska Hargitay, Christopher Meloni) think someone close to her is responsible, possibly her resentful sister (guest star Jill Scott) or r troubled nephew (guest star Quinton Aaron). The case brings to light some troubling truths about the assisted-living business in "Disabled."
Late Show With David Letterman (11:35 p.m., CBS3) - Don Rickles; Piedmont Bird Callers; John Prine; Yim Yames.
The Tonight Show With Jay Leno (11:35 p.m., NBC10) - Comic Kathy Griffin; chef Paula Deen; Hanson performs.
Jimmy Kimmel Live (12:05 a.m., 6ABC) - Jonah Hill; Cat Deeley; Stone Temple Pilots.
The Late Late Show With Craig Ferguson (12:35 a.m., CBS3) - Actor Antonio Banderas; comic Paula Poundstone.