IT ALL BEGAN six presidents ago. Julia Roberts was 3 months old. Tom Cruise and Eddie Murphy were 7. It was 1968, a turbulent year that socked it to the nation’s soul. Old values were shattered by epochal assassinations, Vietnam massacres, Jackie’s marriage to Ari and man’s first journey to the dark side of the moon. Such turning points were wryly noted on a brashly topical new TV comedy show, “Rowan & Martin’s Laugh-In.”Although fights still rage over who created it, “Laugh-In” undeniably stood on the shoulders of Ernie Kovacs, “Hellzapoppin’ ” and old time vaudeville itself, just as “Hee-Haw” and “Saturday Night Live,” stand on “Laugh-In’s” shoulders. Our show was unique in its look, its pace, its writers, its cast. Its imagery was seductive, its rhythm uncontrollable, with no time to breathe between laughs. Its writers took on the world and made the entire cast seemed carbonated. Hosts were co-creators Dan Rowan and Dick Martin. The cast became their repertory group — Judy Carne, JoAnne Worley, Ruth Buzzi, Arte Johnson and me. The first script looked as thick as Schwarzenegger’s neck. Award-winning editor Art Schneider cut seven hours of tape into 500 segments, creating “Laugh-In’s” breakneck pace as he spliced them together by hand. The pilot/special aired Sept. 9, 1967. When NBC reluctantly greenlighted us for the “death spot” (vs. “Here’s Lucy” and “Gunsmoke”), producer Carolyn Raskin predicted we’d become household names. “Yeah,” said cast member Larry Hovis, “just like d-con Rat Poison.” During the first two seasons, the cast expanded to include Gary Owens, Tiny Tim and Lily Tomlin. Two hundred people worked full-time on “Laugh-In.” A dozen brilliant, underpaid writers created reams of comedy. Some six hundred sketches, gags and one-liners were taped each week. Even more were needed to sustain the frenzy. George paid $ 1,000 per joke to New York-based freelancer Jack Douglas, who mailed in wild lines such as Goldie’s “Hi, I’m a cookie. Wanna buy a Girl Scout?” There were notable encounters with a parade of celebrity guests: William Buckley, Ralph Nader, Gore Vidal — everyone from Jack Benny to Richard Nixon. WHEN ARCH-CONSERVATIVE JOHN WAYNE guested, Lily refused to appear in a sketch with him. When Carol Channing performed a dynamite, sequin-sheathed Billy Barnes number with Goldie, we all bet on which blonde bombshell would upstage the other. Smart cash was on the seasoned Broadway star. But, at the big finish, Goldie wagged her shapely behind and won. Irrepressible Sammy Davis was everyone’s favorite guest. He enhanced our performances by joining them — even getting clobbered alongside Arte by Ruth’s handbag. Sammy, a nonstop giver, fed us from huge hampers crammed with gourmet food and marijuana brownies. Poor Kate Smith had had her own show for so long that, when she guested on “Laugh-In,” she usurped director Mark Warren’s role, giving us all line readings. Anytime anyone moved on camera, she hollered, “Freeze!” During her song, we all had to feign heart attacks and fall. Alan landed face-up beneath her tentlike skirt. I couldn’t resist whispering, “Alan — what do you see?” As she belted out her high note, he whispered back, “Irving Berlin!” Soon, hundreds of “Laugh-In” products were flooding the market — greeting cards, lunchboxes, sleeping bags, even franchises for Laugh Inn restaurants. “Laugh-In” had put us all on the map. Twenty-five years later, Dan has, sadly, died. But the rest of us are still working. During a recent trip to Texas, I found an old Laugh Inn. Memories came flooding back: Arte falling down whenever he disliked a musical number, forcing the rest of us to dance around him … head writer Paul Keyes sabotaging Goldie’s cue cards to make her blow her lines and giggle … the excitement of witnessing the birth of dazzling new characters such as Flip Wilson’s petulant Geraldine and Lily’s bratty Edith Ann. Was it really that long ago? Since leaving “Laugh-In,” Henry Gibson has co-starred in 18 feature films and a dozen TV movies. For his role in “Nashville,” he was named best supporting actor by the National Society of Film Critics.