"James Watt" and "Wayne Newton" smiled and nodded from the back of a convertible and "Newton" crooned Beach Boys tunes.

Members of the Georgetown Dental School Drill Team bared their teeth and brandished chain saws, power drills and utility pliers.

An ersatz First Lady carried a sign reading "Gary Coleman in '84."

The Synchronized Precision Briefcase Drill Team, 40 dressed-for-success paper-pushers from the National Institutes of Health and WMAL, twirled their attache cases and marched down M Street through the heart of Georgetown.

It was the "First Annual Trumbull and Core Gross National Parade," and it lived up to its name. More than 25,000 people, according to D.C. police, lined the parade path yesterday from 18th Street to Wisconsin Avenue with lawn furniture and coolers at the ready.

The parade parody, which had a good-natured air of small-town silliness and spontaneity, was the brainchild of WMAL announcers Bill Trumbull and Chris Core, who have been conducting a fantasy on-air April Fool's parade since 1980.

"We couldn't have dreamed up better entries ourselves," said Trumbull of the often ridiculous floats and performing entries that showed up for the real parade.

The Watt/Newton float was concocted at 2 a.m. Sunday by comedians John Simmons, 27, who played Watt in a bald wig and huge wire-rimmed glasses, and James Bowling, 21, a uncanny Newton lookalike.

"We were thinking of doing Rita Lavelle and the Shredettes, but someone was already doing that," Simmons said, although there was no Lavelle to be found. "So we decided the parade needed the right element."

Trumbull, dolled up in a blond wig and garish lavender muumuu, led the parade in a red rickshaw, cracking a bullwhip over Core.

Hot on the heels of the radio team was the first of several Reagan impersonators, grinning and waving from a silver limousine, chanting "Four more years . . . . Stay the course . . . . Help Me Rhonda!"

A crowd favorite seemed to be the "Toro! Toro! Toro! Precision Lawnmower Drill Team," 15 fancy-stepping Kappa Sigma fraternity men from the College of William and Mary, equipped with gleaming red-and-white lawn mowers. The team performed such intricate mower maneuvers as the one-handed "Around the Flower Bed" and "Missed a Spot."

And a parade wouldn't be a parade without a lost child. "We have a lost boy here," announced Core from the reviewing stand. "You can pick him up at the end of the parade. You want a kid, we got a free one for you."

Of course, there was a parade queen. Miss Gross National Parade, an obvious Cherry Blossom Princess reject, was a burly "beauty" with a full beard and red sequined gown, tossing kisses and sardines into the crowd from a battered convertible.

Other sights, sounds and smells at the parade:

Restaurant owner Dominique D'Ermo, in a black top hat, being merrily chased by two "endangered species," a bear and a kangaroo, in an entry entitled "Wild Animal Entrees' Revenge on Dominique."

The Hexagon Players, disguised as chickens, "auditioning," a la "A Chorus Line," for Frank Perdue.

The drum squad of the Cardozo High School marching band, sporting frosted wigs and new wave wraparound sunglasses.

A float manned by the Blue Plains Sewage Treatment Plant, bearing the slogan "For Christmas, Give Sludge, Not Fudge" and tossing dubious-looking samples into the crowd.

The slapdash spirit of the parade seemed to attract some last-minute inspirations. One "float" consisted of a tow truck dragging a battered station wagon, bearing a sign reading "Woodrow Wilson Bridge Victim."

Trumbull and Core conceived of the GNP, which followed Saturday's Cherry Blossom Parade, as Washington's answer to the annual blockbuster "Doo Dah Parade" in Pasadena, Calif.

Proceeds from the parade--the more than 700 participants were each charged a $3 entry fee--are earmarked for the renovation of the Anthony Bowen YMCA, dedicated as the 12th Street YMCA in 1912, then renamed in honor of a freed slave who had established a YMCA for blacks in 1853.