And then there were five ... The Mole (8 p.m., ABC) trudges onward, with the remaining contestants forced to defend their fortress against "foreign aggressors." On a Valentine's Day episode of Buffy the Vampire Slayer (8 p.m., WB), lovelorn Spike is rejected by Buffy, but that's cool, because a certain nutty ex of his has just come back to town. Clothing-optional rapper Lil' Kim guests on DAG (8:30 p.m., NBC). Frasier (9 p.m., NBC) does its version of the Gwyneth Paltrow movie "Sliding Doors," with Frasier meeting the same woman under two different scenarios. Angel and his former posse are both investigating the same case on Angel (9 p.m., WB). Frontline (10 p.m., PBS, check local listings) presents "Hackers," a look at the vulnerability of the Internet.
In the three-part documentary series Secrets of the Pharaohs (8 p.m., PBS, check local listings), scientists use DNA testing on mummified remains to trace the effects of inbreeding on the ancient rulers. Bon Jovi Crush Tour (9 p.m., Fox Family) finds the Jersey hair-metal legends in Zurich, Switzerland, performing their first concert in five years.
Kings at Jazz (8 p.m., TBS)
Rosie O'Donnell (syndicated) Bill Cosby, Ashton Kutcher
David Letterman (CBS) Tom Cavanagh
Jay Leno (NBC) Jennifer Aniston, Ricky Martin with Christina Aguilera
Conan O'Brien (NBC) Bob Costas, Jessica Alba
All times Eastern unless noted.