TONIGHT'S MUST-SEE

"Last Comic Standing," 7 p.m., NBC. There were still eight stand-up comedians last week, but that total dwindles in a hurry. Tonight, we learn which five survived the viewers' vote. Then they perform at the Paris Las Vegas. Three more will be eliminated, setting up next week's two-person finale.

"So You Think You Can Dance," 8 p.m., Fox. This talented field, including Hawai'i dancer Mark Kanemura, is trimmed from six dancers to four.

OF NOTE

"Big Brother," 7 p.m., CBS. Here's the second half of CBS' sudden switch, whisking "Greatest American Dog" to Wednesdays. Now the "Big Brother" eviction is on Thursdays, as in previous summers.

"Grey's Anatomy," 8 p.m., ABC. Here's the first half of a terrific rerun; Meredith and the chief try to save paramedics.

"Mysteries of Shark Coast," 6 p.m., Discovery. Australia's northeastern coast is home to more species of sharks than anywhere else, this film tells us. Now the sharks are disappearing. A team investigates, as the annual "Shark Week" continues.

"Flashpoint," 9 p.m., CBS. This series has moved into the former "Swingtown" slot: A cop is held hostage by an angry family member.

"Fear Itself," 9 p.m., NBC. After being lost in the mountains for days, a rancher returns home seeming changed. An inner-demon battle follows.

"Randy Jackson Presents: America's Best Dance Crew," 8:30 p.m., MTV. With four crews left, Missy Elliott visits. She sings, then watches the crews perform to her music.