"I know your organization was founded by six Washington newspaperwomen in 1919," Ronald Reagan told the Washington Press Club last night. Slight pauce for dramatic effect here. "Seems only yesterday," he sighed.

The place roared. In fact, the new president of the United States was downright funny. Certainly, he was the biggest crowd-pleaser and snappiest deliverer of one-liners at the club's annual fete. The vice president and six other congressmen and congresswomen spoke, but only Rep. Claudine Schneider (R-R.I.) elicited nearly the same amount of laughter as did the former movie actor. And Schneider had to put on a fake nose and moustache midway through her speech.

"I was so frightened that I wouldn't get a laugh tonight that I wanted to do something," she said. "Jack Kemp," she added, meaning the conservative Republican from New York, "does this moustache look too liberal for you?"

The press club's annual "Salute to Congress" is a chance for freshman legislators like Schneider to dliver one-liners, roast-fashion, in front of what is surely one of the nation's cruelest audiences -- the local press corps.

If the three-minute performance is deemed funny, as Sen. Carl Levin's (D-Mich.) was two years ago, the performer can become widely acknowledged as a good guy who is capable of grace under pressure. If you flop, well, you flop. And a lot do.

But not Reagan. With the advantage of an actor and radio announcer's timing and delivery, he popped off such selections as:

"I think that you're taking this honeymoon idea too seriously. I passed a Marriott dirve-in and saw Helen Thomas [of UPI] trying to carry [white House press secretary] Jim Brady over the threshhold."

"It's good to be here with my fellow classmates in the freshman class. Merv [dymally, the new Democratic representative from California] and I came here by way of Sacramento. Merv was the lieutenant governor under Gov. [Jerry] Brown. The difference you'll find here, Merv, is that the flakes are real."

"I hope that all of you [the press club] succeed quickly in your effort to acquire a clubhouse. And if we have our way, and you wait a little bit, there will be several public buildings that will be available."

An enourmous chunk of official and journalistic Washington turned up for the annual event that was bigger than ever this year. Some 1,350 people massed into a Sheraton-Washington Ballroom big enough to hold the B-1 bomber.

But then, this was the first year a president had shown up since Jimmy Carter appeared in 1977. There was also the attraction of all the new administration members, who are still exotic outlanders to many of the locals.

White House political director Lyn Nofziger, for instance, was so exotic as to be wearing Mickey Mouse appliques on the black tie that went with his tuxedo. "It's symbolic of the business I'm in," he explained.

The evening began with a crowded cocktail hour, one of the primary activities being craning your neck to see who among the journalists had brought whom from the administration. Press club members are allowed to invite guests, and generally, they bring sources instead of spouses. There's always a lot of scrambling for the most stellar source and this year, it looked like ABC had gotten the brightest ones: Secretary of State Alexander Haig, National Security Adviser Richard Allen, Secretary of Defense Caspar Weinberger and Soviet Ambassador Anatoliy Dobrynin. ABC President Roone Arledge found himself sitting between Haig and Dobrynin, an interesting twosome considering Haig's recent remarks about the "training, funding and equipping" of terrorists by the Soviet Union.

But Haig said that he and Dobrynin were "old friends." And Dobrynin replied, "I've known him for many years."

And what was Arledge going to do sitting between them?

"Speak Swiss," he replied.

There were also plenty of one-liners about proposed budget cuts in federal programs. But not necessarily funny one-liners.

"I hope they don't do too much too fast," said Sen. John Glenn (D-Ohio). As for OMB Director David Stockman's plans for cutbacks, Glenn replied, "He throws a lot, he asks for a lot -- and he hopes to get half. He might be a lot of bluster."

"Makes you want to cry instead of laugh," said liberal Rep. Morris K. Udall (D-Ariz.). "The country has survived 14 days of Ronald Reagan."

Robert Strauss, Carter's former campaign chairman, was wedged nearby. "Has it just been 14 days?" he asked. "Seems to me I've been out five years."

Pretty soon, presidential counselor Edwin Meese wandered in. "Hi, Bob," he said to Strauss. "How are you? Listen, I apoligize. I haven't called you back."

Not very long ago, it was hard to find anybody who didn't call Strauss back. Immediately.

"What have you been doing?" Strauss' wife Louise asked Meese.

"Oh, nothing," said Meese.

"Listen, have you been gaining weight on this thing here?" said Strauss.

Chuckles, chuckles, chuckles.

The evening, with a dinner that featured "Tournedos with Bedtime for Bernaise sauce," "Where's the Rest of Me?" tomato halves and jelly beans at every table, ended with the audience singing "Happy Birthday" to the president, who turns 70 tomorrow. The event was called "A Night at the Talkies." In the cocktail ara they showed old Ronald Reagan movies and the whole place smelled like popcorn because you could, in fact, get popcorn from a vendor in the corner. One former senator was gobbling his with glee when his wife remarked, "Oh you don't want that."

"Oh yes I do," said the former senator. "I want to eat it while I listen to the monkeys."