‘Invasion’ by Cook on NBC; as Jack Paar ‘Was Saying’ on KCET; 3-D and a ‘Tidal Wave’ hit ABC

Sunday

“Connections 3” / 5-8 p.m. and 8-11 p.m. TLC

Ever eager to learn more about the world around him, host James Burke returns with the third installment of his science-history series. According to Burke, this is a show “that travels across the great web of knowledge through space and time to find the strangest connection between things.” While seeking the “missing links” of history, Burke travels from England to India, filling us in on code-maker Sam Morse, poet Samuel Coleridge, scientist Marie Curie and industrialist Alfred Krupp.

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“Invasion” / 9 p.m. NBC. Concludes Monday at 9 p.m.

Robin Cook, whose medical thrillers range from “Coma” to “Contagion,” switches to science fiction with this aliens-among-us schlock. Luke Perry plays the first of many characters to be infected with nasty flu symptoms by a shiny black stone that drops from the sky. “Sexually, he’s different,” says his perplexed girlfriend (Rebecca Gayheart). He’s also got glowing eyes, scaly skin and an attitude, all part of his mutation into an evil extraterrestrial. “I’m sorry, but this is ridiculous,” says one of the good guys. We couldn’t agree more.

Monday

“Jitters” / 9 p.m. Lifetime

Maybe the casting director for “Jitters” saw Joely Fisher’s character Paige leave the groom at the altar in last season’s finale of “Ellen.” Whatever--she was hired to get cold feet again in this TV movie directed by Bob Saget. Here, Fisher plays the jittery Rita, a conflicted dentist with a fear of commitment (“What if we aren’t strong enough?”) who reluctantly agrees to marry her longtime boyfriend (Brian Wimmer), then breaks off the engagement when the pressure begins to mount.

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“Tidal Wave: No Escape” / 9 p.m. ABC

Corbin Bernsen was credible as the ruthless, rule-bending divorce attorney Arnie Becker of “L.A. Law.” But will anyone take him seriously as a Nobel Prize-winning scientist in this made-for-TV thriller? And would you buy Julianne Phillips as a fellow scientist (an oceanographer, to be precise) who races against time to save one and all from tidal waves created by a madman who “holds the world for ransom”? Yes, we see a potential “disaster” in the making, but not necessarily the sort ABC may have envisioned.

Tuesday

“3-D Week” / 9 p.m. ABC

Anxious to get the edge on its rivals in the hotly contested May sweeps, ABC will try some 3-D imagery to enhance its visuals. For viewers, who can pick up 3-D glasses at Wendy’s restaurants, what does that mean? Well, perhaps Tim and Al will throw “Tool Time” props in your direction on “Home Improvement” or deputy mayor Mike Flaherty will leap into your living room to make a point on “Spin City.” Other series linked to the gimmickry are “The Drew Carey Show,” “Ellen” and “Family Matters.”

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“Six Months to Live” / 10 p.m. HBO

Filmmaker Maryann De Leo focuses on the experiences of four people with incurable cancer on this “America Undercover” documentary. Unwilling to accept a fatal prognosis, each individual (three adults and a child) pursued alternative medical treatments--herbal remedies, macrobiotic diet and Native American spiritual healing--in search of cures that Western medicine was unable to offer. Whether these unconventional methods work remains in question, but the alternatives at least gave the patients and their families some measure of hope.

Wednesday

“Jack Paar: As I Was Saying ...” / 9 p.m. KCET

Witty, well-read and intelligent, Paar was the late-night pioneer who paved the way for the likes of Carson, Letterman and Leno. He discussed religion with Billy Graham, dissected politics with Richard Nixon and once walked off his talk show after NBC edited a joke that referred to a “water closet.” This two-hour “American Masters” documentary marks the 40th anniversary of Paar’s first appearance as host of “The Tonight Show.” Included are clips of Robert Goulet and Judy Garland in a duet gone awry; Jonathan Winters as the “Voice of Spring” and conversations with Richard Burton, Jayne Mansfield and Peter Ustinov.

Friday

“20/20” / 10 p.m. ABC

Former O.J. Simpson prosecutor Marcia Clark gives her first interview regarding the controversial criminal trial to Barbara Walters, who previously has discussed the case with Christopher Darden, Robert Shapiro, Robert Kardashian, Brian (Kato) Kaelin and the family of Ron Goldman.