“So You Think You Can Dance” (7 p.m., Fox) searches for talented hoofers all over the country and asks them to salsa, jive, waltz and hip-hop their way across the floor.

There has to be some kind of law that these shows have a host from Britain. U.K. celebrity Cat Deeley calls the shots on this summer’s “Dance.” She has appeared on Britain’s MTV channel and served as a presenter on the long-running British TV series “Stars in Their Eyes.”

¢ Julia Roberts narrates “Three Days in September” (7:30 p.m., Showtime). Using home movies, news footage and interviews with survivors, “Three Days” recalls the Sept. 1, 2004 siege of a public school in Beslan, Russia.

Chechen terrorists took control of the building on the very first day of school on a holiday in Russia known as the “Day of Knowledge.” Children dressed in their finest clothes and clutching flowers and balloons were among the first and youngest victims of the horror. Nearly 1,200 teachers, parents and children were taken hostage. The siege ended three days later with a bloody gun battle. In the end, 331 hostages died, including 176 children.

Beslan has come to be known as Russia’s Sept. 11. This is not the first film to document this dreadful day. HBO’s “Children of Beslan” aired last September. But, like the bravery of passengers on United Flight 93, which has already inspired three feature-length films, this story bears repeating.

¢ “The Showbiz Show with David Spade” (9 p.m., Comedy Central) moves to a new time. This entertainment “news” show makes the most of its brazenly low budget. While dominated by Spade’s snarky commentary, “Show” is at its best when it lets the celebrity clips do the talking. In a recent, clever bit, “Show” screened an onslaught of snippets from Vin Diesel’s publicity tour for his recent film. In each instance, Diesel faked spontaneity while spouting the exact same words on one clip after another.

Tonight’s other highlights

¢ Cameron Diaz, Drew Barrymore and Lucy Liu star in the 2003 sequel “Charlie’s Angels: Full Throttle” (7 p.m., ABC).

¢ “Everybody Hates Chris” (7 p.m., UPN) recalls the days when videogames were a social activity that got you out of the house.

¢ Faye Dunaway guest stars as a vintage showgirl on “CSI” (8 p.m., CBS).

¢ Boys embark on a mystic quest after witnessing their mother’s murder on “Supernatural” (8 p.m., WB).

¢ Jack’s friend vanishes after leaving a desperate message about his FBI partner’s murder on “Without a Trace” (9 p.m., CBS).

¢ Kovac and Clemente bicker as a patient’s life teeters on the brink on “ER” (9 p.m., NBC).