NOT EVERYONE falls in love at Club Med. Me? I won a medal as a beginning water skier from an instructor built like Conan the Barbarian.

Only when I found myself dancing in step with 600 people, my plastic-bead necklace swaying in time to the resort's theme song, was I sure I'd been Clubbed.That was after a week of sun, sport and personal guidance from Conan, California's blondest bodybuilder. The margaritas didn't hurt, either.

I picked Club Mediterranee as the only affordable vacation with sun-sports/lessons/meals/tips/flights/transfers and congenial company all included. I paid $800 in advance (got a refund on the peso due to devaluation) and put my mind on the rinse cycle.

I chose Cancun, which opened in 1976, because it boasts more sports facilities and an older crowd than the seriously swinging sites like Martinique.

The cost covers a week of windsurfing, snorkeling, scuba diving, water skiing, volleyball, jazzercise, basketball and tennis (on six courts), with group instruction. Guests take it all in or choose to sit by the pool with their Walkman. The 108 "G.O.'s" or gentils organiseurs coax the 615 "G.M.'s" or gentils membres into the proper attitude, yelling, "Smile!" and "My friend, why are you so serieux?" After a few days of franglais, some New Jerseyites adopted the accent.

What you've heard is true: the unlocked rooms are Spartan with two single beds, no TV, a shower and air conditioning. Valuables are checked at the bank.Beads, sold in $8 or $15 bags, are the only currency accepted at the bar. Beads, boutique items and excursions may be charged to your room and settled at week's end. The absence of room keys is a holdover from the days when the club began -- in tents. "We have no more theft than a normal hotel," says Serge Trigano, chairman of Club Med Inc.

The only prohibition concerns drugs: "I don't want to see it or smell it," Cancun's chef du village Patrick Cormery told the G.M.'s gathered at the weekly orientation meeting. Mexican authorities are watching the club carefully, he says; a French G.O. reportedly served five years in jail for possession of marijuana.

The dress code calls for comfort. No matter how lightly you pack, you won't wear half the clothes you take. Shorts or a sundress are considered semi-formal evening wear after a full day in a bathing suit.

Happy hour is no bargain (a Mai Tai costs nine orange beads, about $3.60), and meals aren't as exotic as they might be. Due to the high tax on imports, the food and house wine are Mexican. But local specialties plus frogs legs and quiche are quite good and the lunchtime buffet is endless. Wine and beer flow at lunch and dinner, gratis. Hostesses seat the crowd at tables for eight and a mariachi band serenades diners. Breakfast (omelets, tropical fruits, fresh croissants and rolls, strong coffee, Tang instead of real orange juice) and lunch are buffet style, with service at dinner.

The nightly cabaret is long on costuming and lip-synching -- an effort by the G.O.'s, most of whom are better suited to sports instruction or jobs in the boutique. But the crowd is a pushover, joining in the dance steps and song at the close of each show "Hands up! Baby, hands up, gimme your heart, gimme, gimme . . ." Whereupon cynics retreat to the bar. The disco overlooking the ocean opens at midnight, replete with colored lights and soap bubbles. The beach is a quiet escape from the beat and the hokum.

Celebrity status is conferred on the counselor-G.O.'s by many of the camper-G.M.'s. Typical dinner table opener by a wide-eyed guest to a bronzed G.O.: "What do you think it takes to make a good G.O.?" To summarize: "You've got to enjoy being with people." In most cases though, the G.O.'s physiques outclass their social skills. They are perky party people who mingle relentlessly for six months before being transferred to another Club Med village. Thin and tan, they work long days, rehearsing the evening shows until late at night. Some 90 percent of the G.M.'s are American, 5 to 8 percent European, 2 or 3 percent Mexican and South American. The Americans are mostly Californians and Texans, with the minority of New Yorkers making a pitch for recognition.

We never determined whether Cancun's chef du village Patrick is running for office or for talk show host. He carries his administrative duties to the stage as emcee for the evening entertainment, punctuating each sentence with, "O-kay!" He also acts as host and referee for "Crazy Sports Day."

About 30 of us skipped the day of pink team-versus-black team relays and cheers to see the Mayan ruins at Chichen Itza -- a short plane hop away for $50. Spectacular. We wished we'd taken the day-long bus excursion for a longer tour. The restored pyramid and Temple of the Warriors are even more exciting than the prop's touchdown on a dirt landing strip in the middle of the Yucatan jungle. (We got back in time to witness the body-painting competition.)

Some 130,000 Americans tried "le club" last year, more than half of them for the second time, and the numbers are growing. The club, meanwhile, is updating its image. The summer camp atmosphere, songs and bar beads remain, but the "swingles" days are over. The 92 villages in 26 countries increasingly draw couples (including honeymooners), the middle-aged and children. In fact, Club Med has opened 35 "mini-clubs" for kids in the process of cleaning up its act.

Only a few families attend Cancun each week (enough to irritate more than one young single who asked to be seated at a table free of kneebiters). A vice president for Morgan Guaranty Trust and his wife spent the last week in August there with their three children. "You wouldn't think Club Med would be great for kids," he said, "but it is. They don't enjoy sitting around drinking and reading a book all day, which is typical hotel life."

The closest mini-clubs are at Eleuthera in the Caribbean, Copper Mountain, a new ski resort in Colorado, Fort Royal in Guadaloupe, and Itaparica, Brazil. Luxor is the newest site, offering "no sports but a quiet place to discover Egypt," Trigano says. Construction begins this fall on a club in China close to Canton, due to open in 1984. And the company is eyeing property in Arizona and Key West.

Trigano, son of the Frenchman who started it all in 1950, says, "Ten years ago nobody could imagine putting a computer in a resort." This year three clubs boast computer workshops and video games while ads continue to hawk "the antidote to civilization." Trigano's aim: "To offer the best vacations you can imagine . . . a philosophy of kindness or even tenderness, so that you can come back not only with a beautiful tan but having tried something new."

Frat party rowdiness was one new thing I passed up in college. It was easily passed up again.

I opted out of the fabled picnic, for instance, contenting myself with the description brought back by a wry sociologist. Picnics (usually a day trip from the club) feature lots of liquor, co-ed bathing suit swapping contests and risque party games involving melons. "Nothing special," says Trigano. Topless sunbathers still frequent the pool, but not at mini-clubs, he says. Club spokesmen prefer to emphasize the family-style vacation package: 10 days split between Disney World and Eleuthera, a short hop from Donald Duck to duck a l'orange.

Would I recommend it? If you pack the right attitude. "Don't come to Club Med to have your own corner in the restaurant or your corner on the beach," Patrick advises, sitting in his office beneath a poster reading, "Why Not?" in 10 languages. Treat it like a health spa and enjoy the water sports, with or without a tropical romance.

The peaceful moments are worth the aggravation. Brilliantly colored fish (including barracuda), coral and vegetation make for spectacular snorkeling. At lunch at La Palapa, the smaller, quieter dining room, we watched a champion wind-surfer show off, while a wading ibis drew equal raves in the foreground. Palm trees, hibiscus, bougainvillea and elephant ears were backdrops for our pink three-story accommodations. A pet spider monkey tethered to a tree, salamanders, iguana, sleepy snakes and a soaring albatross moved slowly during siesta hours. We learned the hard way that it's important to take it easy at midday. (Monty's Revenge seems inevitable even if you avoid tap water and go lightly on fruit.)

In the end, wind-surfing classes proved ego-crushing: it takes upperbody strength, good balance and more than a couple of lessons to master the motion. Water skiing was another story.

So was the tequila-tasting party. Conan gave me a kiss goodbye, his blond hair and pink loincloth flapping in the wind. But his muscles ripple on. An artist friend edited two photos into a National Enquirer-style freeze-frame of the barbarian and me, reveling in the spirit of le Club. CAPTION:

Picture, no caption, By Craig Herndon -- The Washington Post