TONIGHT'S MUST-SEE

"Stand Up to Cancer," 7 p.m., ABC, CBS and NBC. The key moment links 15 great voices, for a live performance of "Just Stand Up." There's a youth emphasis, with Miley Cyrus, 15; Rihanna, 20; Leona Lewis, 23; and Carrie Underwood, 25. But there are also pop divas — Mariah Carey, Beyonce, Mary J. Blige, Sheryl Crow and Melissa Etheridge, plus Fergie, Ashanti, Ciara, Keyshia Cole and LeAnn Rimes.The special has more music, from James Taylor, Etheridge and violinist Joshua Bell. There will be humor (Jack Black, and Marge and Homer Simpson) and serious talk about cancer.

TONIGHT'S MIGHT-SEE

"Samurai Girl," 8-10 p.m., ABC Family; concludes Saturday and Sunday. A modern Japanese heiress is startled when her wedding is invaded by killer samurai. She must retreat and fight back. This miniseries has overblown, soap-opera touches, with bad acting in support. Still, it's visually splendid and Jamie Chung is fine in the title role.

OF NOTE

"Dog Whisperer," 5 p.m., and "Dogtown," 6-8 p.m., National Geographic Channel. The entire night eyes the optimistic idea that angry dogs can be rehabilitated. In the first hour, Cesar Millan works with two pit bulls that are at war with each other. Then "Dogtown" rescues four from the dog-fighting venture operated by Michael Vick. The transformation is remarkable.

"Are You Smarter Than a 5th Grader?" 7-9 p.m., Fox. A new season begins.

"NFL Opening Kickoff 2008," 8 p.m., NBC. It's a night of live music for NBC. This special in New York City includes Keith Urban and Usher.

"CBS Fall Preview," 8 p.m., CBS. CBS is still 17 days from its season opening. Still, here's an advance look at a fairly good collection of five new shows.

"Monk," 9 p.m., USA Network. For its 100th episode, the show has a sort of reunion. As Monk works a serial-killer case, a news show profiles him. That brings back guest stars, including John Turturro, Sarah Silverman, Andy Richter and Howie Mandel.

"Swingtown," 9 p.m., CBS. The first (and probably only) season of this series took place in the summer of 1976. That concludes tonight with an end-of-summer clambake.