"Big Brother 7: All-Stars" (8 p.m., CBS): To be honest, we never really got the appeal of this claustrophobic reality series, which plops a dozen strangers into a house and turns them into lab rats.

"Big Brother 7: All-Stars" (8 p.m., CBS): To be honest, we never really got the appeal of this claustrophobic reality series, which plops a dozen strangers into a house and turns them into lab rats. But this time around they're shaking things up a la "Survivor" with an all-star edition, so that could bolster the see-worthy factor. Tonight, a field of 20 former "Big Brother" contestants will be winnowed to 12, with half of the field being decided by fan voting. After that, they'll kiss their privacy good-bye and take up residence in the house, where they'll engage in various challenges, get on each others' nerves and answer some cream-puff questions from host Julie Chen. Of course, cameras will dog them 24/7. The last person standing nabs $500,000.
"The Capitol" (8 p.m., C-SPAN): From its fabled dome to the duties of people who work in one of Washington's most distinctive buildings, the Capitol takes center stage in this encore presentation of a three-part series originally broadcast in May. Each three-hour segment offers viewers a virtual tour and a series of interviews. On Thursday, the Capitol's architecture is explored in "An American Icon." On Friday, the focus is "The U.S. House of Representatives"; on Saturday, "The U.S. Senate."
"Raising the Roofs" (10 p.m., Spike TV): "The Beverly Hillbillies" takes a modernized (and unscripted) turn in this series, in which real-life D-list actor Michael Roof Jr. welcomes his small-town family and their domesticated pig for an extended visit to his Los Angeles home. Following at 10:30 p.m. is The Dudesons, an extreme-stunt comedy based in the Arctic regions of Finland that, coincidentally enough, also features a pet porker.