Many years ago, Rod Serling's "Twilight Zone" did a story about a married couple who, having passed out after an especially manic bender, awoke to find themselves trapped in a prop town of fake furniture, false food, paper grass and prefab trees.

It turns out they had been scooped up in the night by an extraterrestrial daddy and deposited in the doll house of a giant little girl on Mars.

That is what seems to have happened, too, to the characters on "What Really Happened to the Class of '65," the new NBC series premiering tonight at 10 o'clock on Channel 4 and ostensibly based on the despairing and factual bestseller by Michael Medved and David Wallechinsky.

The program's arrival was delayed while NBC henchos squeezed the last drop of despair out of the material.They managed to beat the life, the validity and the daylights out of it as well, however, and now it represents nothing - an anthology of case studies about problems that have little to do with the social or political realities of the '60s or any other time.

Indeed, on "Everybody's Girl," the opening program, the actors wander through standard Universal Studios, Southern California house shells and drive about on streets that looked untouched by anything particularly human. The whole thing exists in a vacuum you keep waiting for the giant little girl to pick up her dollies and go home.

The problem tonight is recurrent nymphomania of an almost lycantropic variety. Annettee O'Toole plays Kathy Adams, a specialist on easy virtue in high school who five years after graduation wants to forget about those "free-love, do-your-own-thing" days and look after her husband, child and interior decorating career.

But then a handsome cad from the past appears and tries to rekindle Kathy's yen for men by the dozen. Instead of submitting, she begins having these fits. She'll be driving along in a car and suddenly start shaking and gasping while a slide whistle makes spooky noises on the soundtrack.

Eventually she runs into a tree and the truth about her high school career comes out; hubbie forgives, she seeks treatment and, says narrator Tony Bill comfortingly, the treatment takes.

Along the way a token effort is made to authenticate the period setting with snippets of old songs that jangle on, oblivious to the story - "Yesterday," "Downtown," and "Call Me," among others.

There's even a word or two from Richard M. Nixon, briefly overheard talking about Cambodia from inside the heroine's television set. She snaps it off without expression and gets back to business - that is, back to the low-grade soap opera that is being asked to pass for her life.