Oprah Winfrey (4 p.m., 6ABC) - Teenagers confront their weight issues during a groundbreaking intervention.

The Chopping Block (8 p.m., NBC10) - With only four couples left, the contestants are challenged first to whip up Italian dishes prepared in 20 minutes and cooked in five, then to serve lunch to Italian customers including Vincent Pastore (The Sopranos), Federico Castelluccio and Mario Batali.

Virtuality (8 p.m., FOX29) - Cutting-edge virtual-reality technology created to maintain sanity during a long space voyage malfunctions and gravely endangers Cmdr. Frank Pike and his crew during their 10-year mission in outer space to save Earth on the brink of environmental disaster.

Everybody Hates Chris (9 p.m., CW57) - Chris tries to break up Doc (guest star Antonio Fargas) and his obnoxious new girlfriend (guest star Robin Givens).

Borat: Cultural Learnings of America for Make Benefit Glorious Nation of Kazakhstan (9 p.m., USA) - Star and cowriter Sacha Baron Cohen and director Larry Charles scored one of 2006's biggest comedy hits with the intentionally outrageous saga of foreign television personality Borat, who comes to the United States allegedly to profile its citizens but really to meet actress Pamela Anderson.

Late Show With David Letterman (11:35 p.m., CBS3) - Actor Martin Short; Regina Spektor performs.

The Tonight Show With Conan O'Brien (11:35 p.m., NBC10) - Rapper Snoop Dogg; Adele performs.

Jimmy Kimmel Live (12:06 a.m., 6ABC) - Actress Megan Fox; actor David Cross; Phoenix performs.