Bob Newhart’s friends and colleagues honor the man with the “Buttoned-Down Mind” as Newhart receives the 2002 Mark Twain Prize for American Humor on the special “On Stage at the Kennedy Center” (8 p.m., PBS). The show includes plenty of clips from Newhart’s stand-up routines and his many TV shows.

Newhart put his name on three television comedies. The first, “The Bob Newhart Show” was a comedy-variety showcase that ran from 1961-62. It featured co-stars Joe Flynn (“McHale’s Navy”) and Ken Berry (“F Troop”). Set in the office of a Chicago psychologist, the second incarnation of “The Bob Newhart Show” ran from 1972-78 and remains a sitcom classic. “Newhart,” which was set in a Vermont inn, ran from 1982-1990, and concluded with what is arguably the greatest series finale in primetime history, when Newhart’s character woke up in bed with Suzanne Pleshette, his wife from the second “Bob Newhart Show,” and confessed that all of the action on “Newhart” had been one long dream.

• Combining science, sociology, history, avant-garde art and popular culture, “Skin” (7 p.m., PBS) covers a lot of ground in just one hour. The National Geographic Special uses advanced special effects to show just how tough human skin can look at the microscopic level, and just how tender it is right below the surface. “Skin” travels to Africa for the painful tribal tradition of scarification. Ethiopian women are whipped to prove their endurance, bravery and family loyalty. Closer to home, “Skin” visits Massachusetts tattoo parlors frequented by Asian gang members and talks with photographer Spencer Tunick, whose specialty is shooting large groups of nude models in public spaces.

Anthropologist Nina Jablonski took the unusual step of “borrowing” a NASA satellite to prove her theories about skin color. Armed with satellite data, she created a map of the ultraviolet radiation patterns of the globe to prove her point that humans evolved with different skin colors to adapt to different environments. “There are no races,” says Jablonski. “There are simply people in different parts of the world with different attributes.”

• John Hurt narrates “The ‘Alien’ Saga” (7 p.m., AMC), a two-hour glance back at director Ridley Scott’s ground-breaking 1979 sci-fi movie and its three sequels. “Alien” reinvigorated popular science fiction, which was then dominated by “Star Wars” and its imitators. It also launched the career of an unknown actress named Sigourney Weaver, who is interviewed here.

Tonight’s other highlights

• Scheduled on “60 Minutes II” (7 p.m., CBS): the inventor of the much-hyped scooter named IT discusses his next big breakthrough.
• Woody Harrelson narrates “Grass” (8 p.m., Sundance), an irreverent documentary about the history of marijuana prohibition.
• A disloyal wife is suspected of her husband’s contract killing on “Law & Order” (9 p.m., NBC).
• Scheduled on “Primetime” (9 p.m., ABC): an interview with Jennifer Lopez.
• The Dixie Chicks discuss their appeal to fans who don’t like country music on “Revealed” (9 p.m., E!). They also chat about their legal tangles with the music industry.

Series notes

• Ed mulls his role at Carol’s wedding on “Ed” (7 p.m., NBC) … Jordan takes his faith lightly on “The Bernie Mac Show” (7 p.m., Fox)… Michael’s sister (Vivica A. Fox) visits on “My Wife and Kids” (7 p.m., ABC) … Archer and Reed face execution on an alien planet on “Enterprise” (7 p.m., UPN) … The gang attend a No Doubt concert on “Dawson’s Creek” (7 p.m., WB).
• Dance fever on “George Lopez” (7:30 p.m., ABC).
• The guys open a hip nightspot on “Fastlane” (8 p.m., Fox) … Aaron’s discards dish on “The Bachelor” (8 p.m., ABC) … A man succumbs to a virtual temptation on “The Twilight Zone” (8 p.m., UPN) … Helena infiltrates a gang on “Birds of Prey” (8 p.m., WB).