TONIGHT'S MUST-SEE

"Comic Relief," 7 p.m., HBO and TBS. Many of the world's funniest people combine to raise money for victims of Hurricane Katrina. That includes the usual hosts — Billy Crystal, Whoopi Goldberg and Robin Williams — plus other top comics. The lineup (subject to change) has Jon Stewart, Ray Romano and Roseanne Barr. It also has Lewis Black, Louis CK, Dane Cook, D.L. Hughley, George Lopez, Rita Rudner, Sarah Silverman and more. Expect large laughs.

OF NOTE

"Taxi Driver" (1976, AMC) and "Apocalypse Now Redux" (2001 re-editing of 1979 film, Bravo) Both at 6 p.m. Martin Scorsese and Francis Coppola have been heralded as two of the strongest forces for bringing a new artfulness to American movies. Now Scorsese's "Taxi Driver" is alongside Coppola's "Apocalypse Now."

"Dateline," 7 p.m., NBC. For the second straight Saturday, NBC has shuffled its plans, inserting two hours of "Dateline."

"Law & Order: Special Victims Unit," 9 p.m., NBC. In this rerun, a mother and daughter have been brutally raped. The prime suspect is a senile, homeless man, played by Jerry Lewis.

"Saturday Night Live," 10:30 p.m., NBC. Since Ludacris is both an actor and a singer, it makes sense that he'll do both tonight. He's the host and the musical guest.