United against cancer

As much as we talk and write about the power of the Internet, it is easy to forget that nothing focuses the nation's attention on a topic or event like TV - particularly the combined gaze of cameras from the major networks of ABC, NBC and CBS. That's the case tonight when the networks and a huge group of Hollywood A-listers present Stand Up to Cancer.

All three network news anchors - Katie Couric, Charles Gibson and Brian Williams - will be reporting stories on medical advances and efforts. The list of participants includes Meryl Streep, Charlize Theron, Forest Whitaker, America Ferrera, Kenneth "Babyface" Edmonds, Lance Armstrong, Beyonce and Sheryl Crow. (8 tonight, ABC, NBC and CBS)

BACK ON SUNDAY HBO's Entourage returns for Season 5 on Sunday, and even Vince, the Hollywood golden boy, has money woes. Now I know the economy is in trouble. ** 1/2 (10 p.m. Sunday, HBO)

ALMOST FABULOUS Sundance debuts another winner Sunday night with The Life and Times of Vivienne Vyle, a BBC spoof of the world of TV talk shows. How is this for two headliners: Jennifer Saunders (Ab Fab) as Vivienne Vyle, a nasty daytime talk-show host who channels an inner dominatrix, and Miranda Richardson as her self-absorbed producer. The first of six episodes is loud and nasty - in a good way. *** (9 p.m. Sunday, Sundance Channel)

LATE-NIGHT GUESTS FRIDAY The Tonight Show With Jay Leno: actress Eva Mendes. Late Show With David Letterman: actor John Malkovich.