Once I cut-a-rug with the best of them. I did a smooth waltz, a mean Charleston and a wild jitterbug. While the music played, it was impossible to get me off the floor. I'd arrive home bursting with energy.

But lately, as a member of the Prime Time generation, I've sought more sedentary pleasures: bridge, calligraphy, gourmet cooking. When a friend presented me with complimentary passes for the opening of his New Wave group, I decided it was high time for me to go discoing . . . err, dance rocking, while I still could.

I arrived at the club, dressed in jeans and velour shirt, garb I hoped would be appropriate. Since the pass was for two, I was accompanied by my husband, a gent notorious for his two left feet. At 9 p.m., the time marked on the ticket, the showcase for up-and-coming rock groups was dark and deserted. Was it closed? Did I have the wrong day? I began to have second thoughts about the whole idea. "They've got 'till 9:30," my husband muttered.

But just as we started to pull away, the marquee lights blazed on. The music scene obviously has a time zone of its own.

I paused at the door. "I.D. please," the ticket lady insisted. Good grief, the last time I'd heard that request was several decades ago. She must be kidding. Maybe the darkness had hidden the time-etched lines around my eyes? Whatever. Few middle-aged pleasures can compete with being taken for under 21.

My husband suggested glasses for the young lady as he entered behind me--unquestioned.

In the flush of mistaken youth, I entered the cavernous hall where flickering spotlights played hide-and-seek around the dance floor. I missed the revolving silver ball that had sprinkled light on couples gliding around old-fashioned ballrooms. As groups and singles drifted in, it was soon apparent that today's dance halls are the exclusive domain of the Pepsi generation. The age of this crowd probably averaged 24, half of ours. What were we doing here?

"No live music 'til 10:30," said a clean-cut lad, incongruously sporting a Sex Pistol T-shirt. I hoped I could stay awake. My husband revived when he discovered the bar was open. Others sought courage there too. No one ventured onto the floor, though there was an explosion of "canned" sound from the huge speakers lining the wall.

The show started with a blast of highly amplified Moog, drums and guitar, screaming the group's frustration with themselves and the world. My husband, no John Travolta, remained at the bar and offered to dance if and when they played a waltz.

Stricken with Saturday Night Fever, I joined our friend in a booth. How I wished for one of those singles drifting around the room to overlook my age and offer a chance to trip the wild fantastic. A long-forgotten wallflower smile reappeared from my past and pasted itself on my lips. My psyche was still cemented in the '50s, when the girl had to wait to be asked to dance. It looked like I would be spending the evening in a booth watching, not dancing.

Then I realized the current breed of dancers was indeed liberated. Girls sauntered around, found partners. Either sex--it didn't seem to matter. When the rhythm became irresistible, painted and costumed "punkers" jumped up and stomped and leaped in solo contortions.

Pushed by the insistent music, my body took on a life of its own. My toes tapped wildly. My shoulders pivoted like pistons. My head swiveled, punctuating the music. Da, da, da, dee, da. If it is possible to dance in your seat, that's what I was doing.

Then, oh joy! A youth, whose heavy beard added age to his baby face, approached. "Don't I know you?" It was probably just as well that the whine of the synthesizer blurred my rejoinder. "Yes. I probably play bridge with your mother." His old, familiar line reassured. Things hadn't changed that much.

So when he took my hand and whirled me onto the floor, any reluctance vanished. My husband waved from the bar. I didn't know the steps, and started awkwardly. But I was soon caught up in the joyful exuberance spilling across the discothe que. The pulsating beat reached a core of pure rhythmic energy deep inside me and broke it loose. Everyone did their own thing. I did mine.

Yet it wasn't quite the same. I didn't have that manic spirit anymore. My knees creaked. I began to feel my years after three dances. I thanked my partner and retired to the booth where my husband joined me. He had liked watching, said he found my mood contagious. We stayed until the end of the second set, enjoying the lyrics as insightful commentaries on today's mores. The earplugs I'd tucked into my purse earlier remained unused.

At 1 a.m., we headed for my matronly station wagon. A burly late arrival in a down vest called, "Where you goin'? It's still early."

I looked back wistfully. Time may have diminished my staying power, and I felt somewhat overdosed on high decibels but the old urge towards terpsichorean pleasures had been revived. "I'll be back," I called. "'Another time."