This guide is designed to alert readers to the scope and variety of programming coming up. Listing is not meant to represent blanket endorsement. Viewers are urged to be selective. FRIDAY The House on the Waterfall (PBS, 10:30-11 p.m.): A show about a house - but what a house! It's ``Falling Water,'' Frank Lloyd Wright's masterpiece on Bear Run in the Laurel Highlands of southwestern Pennsylvania, called by many architects the best American building in the past 125 years. SATURDAY A Waltz Through the Hills (PBS, 8-9 p.m.): First of a two-part ``Wonderworks'' story, based on the book by G.M. Glaskin, about the adventures of a boy and his young sister in the Australian outback.
SUNDAY Men's Olympic Marathon Trial (ABC, 1-3 p.m.): ``The New Jersey Waterfront Marathon'' kicks off the 22-hour coverage of the trials. The first three winners represent the US in the Games of the XXIV Olympiad in Seoul. NBA Basketball (CBS, 3:30-6 p.m.): Live from Chicago, the Boston Celtics clash with the Chicago Bulls in an Eastern Conference game as the regular season draws to a close. It's About Time (TLC - The Learning Channel - 8 p.m.): Age 55 begins a life bursting with fun and fulfillment, according to the premi`ere of this new series about older people having the times of their lives. April Morning (CBS, 9-11 p.m.): Dramatization of the noted 1961 Howard Fast novel, focusing on a 15-year-old boy and the British-American clash at Lexington, Mass., an early step on the road to revolution.
MONDAY Alaska at War (PBS, 10-11 p.m.): The first time since the War of 1812 that a foreign power held territory on US soil was the Japanese occupation of the Attu and Kiska Islands in Alaska in World War II. This show looks at the startling results. Nightline (11:30 p.m.-12:30 a.m.): First of a week-long series of live Ted Koppel broadcasts from Jerusalem reporting on the vortex of issues in that troubled area - strategic, political, sociological.
TUESDAY China Beach (ABC, 9-11 p.m.): American women and their overlooked but often crucial role in the Vietnam war is the subject of this premi`ere of a limited-run series. The regular program begins April 26, 10-11 p.m.
WEDNESDAY Metropolitan Opera (PBS, 8:30-11 p.m.): Jessye Norman, Kathleen Battle, Tatiana Troyanos, others in Richard Strauss's opera-within-an-opera, ``Ariadne auf Naxos.''
THURSDAY Max Headroom (ABC, 8-9 p.m.): The electronic man returns in this premi`ere of a new season of original episodes. Listings are in Eastern time; other zones may vary. Please check listings for all PBS programs, since local option often results in differing days and times.