They've come back, their faces burnished by the very best sunshine, their tennis rackets scuffed (or, preferably, grass stained), and now it's time to buckle down, to get serious. Time to take out the datebooks and the silks; time to call the caterer; time for The Important and their social secretaries to stand over their desks sorting envelopes with the speed of crazed Christmas mailmen as they rate the invitations on a scale from 1 to near-infinity.

The Season has begun, parties are starting.

And even if it's less than a week since Labor Day, what with the planning and the RSVPing and the political-tightrope-walking, the givers and goers are already a little out of breath.

"It's such a wonderful lazy life in the summer," says inveterate party-goer Buffy Cafritz, "it's hard to start thinking about hair and clothes and everything. We live in jeans all summer."

But the vacation is over. With each September, a certain 5,000 or so Washingtonians are barraged with invitations to meet, greet or scramble for a seat at dinner parties, cocktail parties, book parties, hotel ballroom luncheons, charity balls, breakfasts from prayer to champagne, intimate lunches and strategy brunches, receptions, tributes, testimonials and roasts, annual dinners, art openings, fetes and galas and public relations extravaganzas, fundraisers for politicians, fundraisers for museums, fundraisers for assorted good causes; and then there are are the invitations for what Ridgewell's Caterers coowner Jeff Ellis calls "small, intimate parties." For Ellis, small and intimate means 500 guests instead of 2,000.

Over the next 10 days, for instance, the party people can get back in the mood by making their way through a calendar as varied as the best-catered buffet. Consider:

The Parties with Politicians: The Republican Majority Fund's roast for Sen. Howard Baker (R-Tenn.), featuring the combination of Republicans and jokes; the gathering for the Committee for a Free Afghanistan, featuring congressmen and Afghans; the eighth annual Atoka Country Supper at Sen. John Warner's (R-Va.) farm, featuring Virginians, clog dancing, barbecue and bluegrass.

The Mill-and-Mix-and-Munch-and-Mingle Parties: the Canadian Embassy's Fall Reception, the Israeli Embassy's reception for a visiting dance troupe, the English Speaking Union's open house where you can chat with a beefeater and sample a variety of gins.

The "Can't-You-Fit-Just-One-More-Lunch-In?" Lunches: Norman Lear's People for the American Way lunch and Barbara Bush's lunch for the wives of the chiefs of diplomatic missions.

The Conscience-Salving Parties: the Wolf Trap Ball, the Cystic Fibrosis Ball and the Ambassadors Ball to benefit multiple sclerosis research.

The Parties With Books: Rep. Claude Pepper (D-Fla.) will answer questions at the party for his book "Ask Claude Pepper" and Arnaud de Borchgrave and Robert Moss will sign copies of their "Monimbo."

The Parties With Boats: The presidential yacht Sequoia homecoming. For only $500 a person, you can go on board and it's tax-deductible.

And this is only the very, very, very beginning.

Ah, yes: one day you're furling the jib in Seal Harbor, the next day wading into the stuffed pea pods, the dates wrapped in bacon, whatever the fashionable hors d'oeuvre is in Washington this season. It can all be kind of disorienting, especially in a presidential election year.

"I think it is overwhelming when so much is going on every evening," says PR woman and party organizer Mary Pettus. "In an election year there is so little time for everyone to do their parties because Congress is here for so little time. The competition to get those VIPs to your party is very keen."

And then there are those special election year nightmares. Imagine finding yourself sitting next to just the person you shouldn't and saying something indiscreet about the election, or throwing a big party for a candidate just before his devastating defeat at the polls.

"It's terribly important in mid-November to be able to say, 'I was there all along,' " says American University president and veteran circuit rider Richard Berendzen. "This is part of the integrity of the city."

So on this fall's runaround, caution will be almost as popular as sushi.

"There are a lot of wait-and-sees," says Cafritz.

"People get kind of tense and a little tight and a little testy this time of year," says conservative direct-mail fundraiser Richard Viguerie. The most tense, he says, are those politicians and lobbyists who most of the time manage to sail easily from Republican to Democratic circles and back again. Just now, the course may be a little harder to navigate than usual.

"Someone you might like very much and enjoy talking with," he says, "you might not see much of right now because you have such strong feelings."

But even if a wary few are looking forward to Nov. 6, when all doubts will be resolved and parties can get back to normal, most socializers are worrying about more routine problems.

Like convincing themselves it's that time again.

"People aren't fully conscious at this point," says Jayne Ikard, journalist and wife of former Democratic congressman Frank Ikard. "I think they're doing the kind of things they should have done before the summer ended, getting their wardrobe in order and so on."

Ikard is currently trapped in Martha's Vineyard, waiting for her daughter-in-law to give birth to twins. The babies are late and the grandmother-to-be is eager to move on.

"It was great while the weather was nice," she says. The weather's not so nice any more and invitations and board meetings are waiting in Washington.

Then there's the problem of fitting it all in.

"It's nice to go to these things," says Sen. Bob Dole (R-Kan.), "if you don't work."

Dole says he plans to restrict his after-hours activities to the obligatory fundraisers for his and fellow Republicans' campaigns.

"The social part, we don't do a lot of that," he says. "If you can sort of hit and run, go in and say hello to the honoree and leave . . . But if you have to drive around all night to find them, that's not my idea of a pleasant evening."

The "hit and run" technique is doubly effective. Not only does it mean you might get to bed by a reasonable time, it also gives you the special social glow that surrounds the men and women everyone sees everywhere.

There are other methods.

"I find the best thing is to get up early in the morning and walk in this beautiful city," says Ulla Wachtmeister, wife of the Swedish ambassador. "When I do that I feel I'm much better organized.

"Some days there are too many things . . ." she says, but banishes the thought before the words even have a chance to fade. "It's just a question of getting organized and taking a walk in the early morning."

Another popular alternative is just not going to anything at all.

"I'm trying not to, very deliberately and consciously," says Viguerie. "I'm counseling all my friends and colleagues to stay home, only go to the trips and dinners that are critical to the November 6th election. There'll be plenty enough time to socialize after the election."

But however they've prepared for the onslaught, it's never enough, and they repeat the perennial vows: no more, it's too much, next year I'll learn to say no.

"It does begin to sweep over you, all the commitments you made without thinking about it," says Ikard wearily. "I always tell myself I am going to stay up here till Thanksgiving but I've never done it.

"This is beautiful -- I have a garden and a lovely house and the water -- and yet it isn't really the real world. If you didn't do that, this wouldn't be so perfect and fresh. You need the contrast. It's like everything. A good play ends before you're ready for it to. You want more. It's like making the exit at the proper time at a party."

And the Season begins.