TONIGHT'S MUST-SEE

"Sex: The Revolution," 5 p.m. to 9 p.m., VH1; and "Swingtown," 9 p.m., CBS. One show is a long, documentary rerun; the other is a new, fictional hour. They fit together, however, reminding us how much the world has changed.The first "Sex" hour shows the 1950s view that sex is strictly for married couples. It adds some hints of change, including Playboy magazine and the arrival of birth-control pills. In the second hour, life loosens in the 1960s; there are topless bars and porno films. In the third, the gay-liberation movement emerges. And in the fourth, the down side to freedom becomes clear. AIDS develops, sexually transmitted diseases increase, the women's movement questions the one-sided nature of this revolution. All of this is done quickly and slickly, with lots of clips and interviews. Meanwhile, the same themes are reflected fictionally in "Swingtown." That series is set in 1976, in a suburban-Chicago neighborhood that takes its swinging seriously. Tonight, Trina hosts a "puzzlerama" party. She splits the couples into new combinations, then has them solve puzzles, based on neighborhood secrets.

"Last Comic Standing," 7 p.m., NBC. There are only three episodes left, so this show must move quickly; tonight, it trims from eight comedians to five. Still, it does have some room for detours. Tonight, it visits the mansion of Hugh Hefner; his three girlfriends are in their lingerie, on a big, round bed. The comics must tell them funny bedtime stories.

OF NOTE

"Superman" (1978), 7 p.m., Ion. This might not compare to the mega-budget epics now, but it has fun, flair, humor, romance and a great cast. Christopher Reeve stars, with Margot Kidder, Gene Hackman and even some fatherly advice from Marlon Brando.

"Ugly Betty," 7 p.m., ABC. Henry isn't happy about it, but he takes Betty on a double date with Hilda and Gio.

"CSI: Crime Scene Investigation," 8 p.m., CBS. Here's the rerun of a particularly good episode, from the time when William Petersen was away from the show doing a play. Filling in was Liev Schreiber as Keppler, who brings a different sort of ethical view. Tonight, his plan includes a fake crime scene.

"So You Think You Can Dance," 8 p.m., Fox. It's time to trim the field from eight dancers to six.

"Grey's Anatomy," 8 p.m., ABC. Here's a particularly strong episode, sparked by a school-bus crash. As the hospital fills with teens, Dr. Bailey meets the guy she had a crush on in high school.

"Fear Itself," 9 p.m., NBC. Brandon Routh ("Superman Returns") and Shiri Appleby ("Roswell") play a pleasant couple, moving into a pleasant-seeming neighborhood. They soon learn how far the neighbors will go to enforce conformity.

"Black in America: The Black Man," 9 p.m., CNN. The well-crafted documentary mini-series concludes with a mixture of hope and despair.

"My Boys," 10:40 p.m., TBS. Bobby's bothered on all sides. His wedding preparations are getting tangled; also, his brother (a womanizer) is making a pass at PJ.