What to watch for the week of April 20 -- A day-to-day guide to notable programs

FRIDAY, 4/20
Dolphins, Whales and Us Model Elle Macpherson, Olympic swimming medalist Matt Biondi, and thirtysomething‘s Peter Horton strap on their flippers and communicate with their aquatic costars in a documentary. CBS (8-9 p.m.)
Movie: That’s Life! Writer-director Blake Edwards in a seriocomic mood: Jack Lemmon has a crisis over his 60th birthdat while his wife (Julie Andrews) endures a wait for biopsy results. CBS (9-11 p.m.) B-
Hardball After five months of fine-tuning, a cop series a aut a middle-aged warhorse (John Ashton) and a young rebel (Richard Tyson) returns with less talk and more action. NBC (10-11 p.m.) Save the Planet: A CBS/Hard Rock Cafe Special It’s Earth Day: the Party Weekend as Bob Goldthwait, Billy Idol, Alice Coooper, M.C. Hammer, and others gather in L.A. to educate and entertain the masses. CBS (11:30 p.m.-12:30 a.m.)

Cartoon All-Stars to the Rescue An across-the-dial simulcast of a drug special in which the Smurfs, the Teenage Mutant Ninja Turtles, Winnie-the-Pooh, Alf, and a gallery of toons team up to keep a teenager drug-free. ABC, CBS, DIS, Fox, NBC, NIK, USA, others (check local listings) (10:30-11 a.m.)
In Living Color Keenen wit: A skit-comedy ensemble led by Keenen Ivory Wayans ananrubber-faced impressionist Jim Carrey settles into its regular time slot. Fox (9-9:30 p.m.)
Saturday Night Live The last live one for a few weeks features Miami Bluesman Alec Baldwin as host and the always festive B-52’s as musical guests. NBC (11:30 p.m.-1 a.m.)

SUNDAY, 4/22
The Earth Day Special Earth Day’s 20th anniversary is commemorated with music and skits, with Bette Midler (as Mother Earth), Meryl Streep, Bruce Willis, Barbra Streisand, and others. ABC (9-11 p.m.)
Movie: The Investigation Inside a Terrorist Bombing John Hurt plays British reporter Chris Mullin in a docudrama that probes the Birmingham Six case in England, in which six Irishmen were sentenced to life in prison for 1974 pub bombings. HBO (10 p.m.-midnight)

MONDAY, 4/23
Kids’ Choice Awards Full House‘s Dave Coulier presides over the honoring of top vote-getters selected by kids in 12 categories, including music, movies, and sports. NIK (7-8 p.m.)
Miniseries: Voyage of Terror — The Achille Lauro Affair Burt Lancaster and Eva Marie Saint play terrorist victims Leon and Marilyn Klinghoffer in a two-part, four-hour drama, filmed aboard the Achille Lauro, that re-creates the cruise ship’s 1985 hijacking. Syndicated; check local listings.

Miniseries: Not a Penny More, Not a Penny Less Jeffrey Archer’s adventure novel about four men who unite to seek revenge on the wealthy con man who swindled them becomes a miniseries; Ed Asner, Ed Begley Jr., and Jenny Agutter star. USA (Part 1: 9-11 p.m.; Part 2: Wed., 9- p.m.)
The Best of Nightline With Ted Koppel 1980-1990 Fun for Tedheads: A prime-time retrospective re-examines Nightline‘s first 10 years. ABC (10-11 p.m.)