WORTH NOTING ON TV

* THURSDAY

Hal Roach: Hollywood's King of Laughter (The Disney Channel, 9-10 p.m.): Some of America's great comic traditions owe their start to a man whose name still looms large in Hollywood, even though he was born more than 100 years ago: the late film producer-director Hal Roach. He perfected the art of slapstick with Laurel and Hardy and with Harold Lloyd, developing a style that put one outrageous physical gag on top of another - often ones that seemed to threaten the comic hero with mayhem - until audiences didn't know whether to laugh or scream. They usually chose the former, and his studio became the place to be in Hollywood if you were a comedy actor.

Full of clips from Roach films and unusual archival footage, the special is narrated by Penn Jillette of the Penn and Teller comedy team. It offers interviews with an array of today's comedy names, among them Mel Brooks, Steve Allen, Dom Deluise, and others. * FRIDAY

Talk Radio Week (C-Span, 5:30-10 a.m., EST): The channel is devoted this week to simulcasts of radio talk shows. Today it's ``The J.P. McCarthy Show,'' from Detroit's WJR.

Lives In Hazard (NBC, 8-9 p.m.): How youth gangs operate, the mayhem they commit, and especially how they pull recruits into their ranks - these are some of the topics covered in this documentary about a social crisis in the United States.

It has an unusual executive producer: Edward James Olmos, who won an Emmy for his role as a police officer in NBC's ``Miami Vice'' (1984-89) and was also an Oscar nominee for his performance as an educator in the 1988 film ``Stand and Deliver.''

Drugs and guns are among the problems probed, but Olmos - who also narrates the special - takes an especially close look at East Los Angeles, where he once lived. There and elsewhere, as the program shows, young people are are often without roots or role models, and they turn to gangs as a kind of social haven and protection.

Please check local listings for these programs.