The crowd is crushing. Bear hugs are being exchanged liberally. Moving among the shoulder-to-shoulder bodies in a skin-tight proposition. At the heart of the party is a table laden with delicacies, among the, brie cheese topped with caviar, an explosively hot curry and ceviche. Champagne corks pop regularly.

The party spills outside onto the front stoop where a lanky man with thinning, brown hair (who writes military position papers for John Anderson) is describing his fellow revelers for a visitor. They're divided, he says, into three categories: The lustful ones; the typical, smart lustful ones, and the outright perverse.

The sum of the parts is not greater than the whole.

It's a Mensa party. An exceptional gathering for exceptional people. Its members have papers stashed in a personal file or bureau drawer somewhere certifying them as exceptional in terms of intelligence. Some of their hapless dates, however, are from the other side of the IQ cutoff.

Mensa is the Latin word for "table." It is also the name of a social club whose members can prove they scored in the 98th percentile on one of many intelligence tests. The "table" connection, according to one member, comes from the idea of "a round table at which all are equal."

Mensa personalities seem to run the gamut, and members are quick to point out to visitors that some of them qualify as a trifle strange by everyone else's standards.The explanation likely to follow is that genuises are weird.

"I thought (Mensa) would be an elitist, snob operation, but it's the most democratic organization I know," David Hume, Mensa's regional vice chairman here, said. "We have housewives, PFCs (privates first class), high school dropouts."

Then, ever so serious, he adds, "We also have a lot of strange people, with neuroses."

Long-time Mensa members like Dale Davis revel in their eccentricity.

His occupation?"I'm a bum," he says. Pressed on what he has done with his life, a smirk: "Nothing at all has happened." How then does he support himself? A slight, goateed man, he proudly models his "thrift shop clothes," and begins a discourse on how to subsist on berries and other fruits of the wild.

After inviting a visitor to an upcoming nudist gathering in Massanutten Mountains, Davis offhandedly mentions his efforts to find a publisher for his recently completed life's work -- a book he calls "a universal explanation of all things."

George Koplow, a 20-year-old Mensa veteran, tried to describe the typical Mensa personality.

"All Mensa members are arrogant," said Koplow, a real estate agent from Potomac. "They assume their mental superiority and their social inferiority. Most are frustrated in their employment and feel they're smarter than their bosses."

Mike Tuchman, who at a recent 'Mensa open house wore a T-shirt proclaiming himself a "Super Accountant," attested to the anti-snob mentality of the club.

"We have people ranging from, those sponging off welfare to those with income in six figures," he said. Just like everyone else.

The metropolitan Washington chapter of Mensa has about 1,500 members. Nationally, the group claims some 40,000. Its membership grew by an estimated 10,000 people last year, the largest single-year increase in the U.S. organization's 20-year history. (Mensa began, predictably enough, in England in 1945.)

Active members here attribute the sudden surge of recruits to media attention. Playboy and Omni magazines had pieces, the Tank McNamara comic strip had a mention, but they specifically point to a story in Reader's Digest last year which included a sample qualifying intelligence test.

"The Reader's Digest story brought 80,000 entries," said Amy Shaughnessy, secretary for Washington Mensa. "But some weren't eligible. And we always lose a lot of people after their first year (of membership). They find out we're not the intellectual snobs they thought we were. It's a social group, not an intellectual group."

Shaugnessy said members of the local group, who come from D.C., Maryland, Virginia and Harper's Ferry, W.Va., hold about 30 to 40 parties a month in different places around the area.

These gatherings range from dinner among the belly dancers at the Astor Restaurant and poker games for nonsmokers to Hawaiian Iuaus, tea tastings and toga parties. Cookouts, yard sales and birthday parties are among the group's more conventional activities.

The Washington Mensa club also organizes "special interest groups," abbreviated to "SIG," that concentrate on activities such as cooking, poetry, theater, parapsychology, economics and human rights. Then there is "DAMSIG," the Dirty Adult Movie Special Interest Group; "SEASIG," the Safe Energy Alternatives Special Interest Group, and the M-Phillumenists group, which members translate to "Mensa Matchbookers."

In defense of unique Mensa activities such as the dirty adult movie group, Hume said members who attend have "no prurient interest," they're "not the raincoat crowd."

The overriding reason given for joining the club is that it offers a chance for people to meet people. But it is also a source of social events for individuals who consider themselves more interesting than others because of their higher IQs.

As one official brochure says, "Mensa returns to the Renaissance man who knows enough about everything and is not afraid to find out more when he needs to."

"Most intelligent people have intelligent friends," the brochure reads, "but they usually come from one circle, profession or discipline. Mensa is the last stand of the intelligent against the encroachments of professionalism and sectional interest . . . Mensa is protean. It helps make you an all-round person."

In addition to the wide variety of social events the Washington Mensa chapter offers, it also provides services such as job listings and a monthly newsletter that publishes classified ads and free-lance poetry, elements that ultimately coalesce into a loosely-knit group whose members can feel secure and comfortable with one another.

And if it seems to stray, Mensa provides the basis for a reprimand. A note in one recent newsletter put it this way.

"Unwritten rule becomes writ (not code): In Mensa we do not use intelligence as a target for insult. We joke a lot but we don't deride another's high brain power. We get enough of that from the rest of the world -- we don't need it from each other."