Britain's Prince William, who turns 18 Wednesday, is profiled on a new Biography (8 p.m., A&E). If Prince William were a contestant on Survivor (8 p.m., CBS), how long would he last? Well, he's pretty rugged (not to mention pretty pretty); I think the women on his team might want to keep him around. As for President Bartlet, who reveals a secret about his health tonight on a rerun of The West Wing (9 p.m., NBC), he'd be booted off the island in record time, once he started in with his long-winded quotations from ancient Greek poetry. That brings us to Felicity (9 p.m., WB), who participates in a sit-in at the clinic in tonight's rerun to protest the college's heavy-handed policies. She's plucky, she's persistent, she could probably force herself to eat bugs and cut the heads off rats if she needed to. Yes, Felicity's a survivor -- until she drives her teammates insane with her well-meaning interference in their personal lives. Hand over the torch, missy, you're outta here. South Park (10 p.m., Comedy Central) has a new episode in which Cartman finds some mature friends over the Internet. Can you say NAMBLA? Cartman's chances on "Survivor": He'd be the contestant most likely to go mad and become an island despot, like Marlon Brando in "Apocalypse Now."
ABC's afternoon soaps commemorate the annual Day of Compassion (12:30 p.m. to 4 p.m., ABC), which recognizes those living with AIDS, by airing AIDS-themed episodes of "Port Charles," "All My Children," "One Life to Live" and "General Hospital."
Cubs at Braves (7 p.m., ESPN)
Yankees at Red Sox (7 p.m., ESPN2)
Rosie O'Donnell (syndicated) Robert DeNiro, Michael Michele
David Letterman (CBS) Dana Carvey, No Doubt
Jay Leno (NBC) The Rock, Christina Aguilera
Conan O'Brien (NBC) Sam Donaldson, Sebastian Bach, Todd Rundgren
Craig Kilborn (CBS) John Singleton