They didn't save it for the dance floor at Saturday's Brazilian Carnaval. A boisterous group of partygoers from Washington's Brazilian community livened up the lobby of the Shoreham Hotel as they sambaed through its hallways, loudly chanting a song praising cachac,a, a powerful Brazilian rum, and looking for Washington's own version of Brazil's week-long madness--Carnaval.

"It's a hell of party," laughed host Felix Grant, in black tie and rhinestone shirt studs, at the eighth annual Brazilian Carnaval at the Shoreham's Regency Ballroom. Grant, who has a long-running, late night jazz show on WMAL, is president of the District of Columbia Partners of Brasilia, and with wife, June, engineered Saturday's event. "We throw this every year as a fund-raiser for our other programs. We have an intense interest in exchanges of all kinds: sports, entertainment, all sorts of things."

Inside, it was more fun-raiser than fund-raiser. Herds of normally staid Washingtonians charged onto the dance floor the instant the fevered rhythms of famed Brazilian percussionist Dom Um Ramao and his 18-piece samba band began, not pausing to loosen up with one of the potent potions imported for the occasion.

"Brazilians don't use the word costume--they call them fantasi'as," Grant grinned, as several slinky fantasi'as wiggled by. "Americans are very inhibited about wearing costumes. Looks like they've gotten over it tonight." Grant tried out his apito, a Brazilian party whistle he "picked up in Bai'a."

Gaily decorated tables remained largely vacant, as over 1,000 guests undulated in samba lines, singing the cheerfully repetitive Portuguese and Spanish words, and adding to the urgent polyrhythms with maracas, tambourines and shrieking whistles. They even danced in the drink queues. Batidas, made with cachac,a, were plentiful, as was imported Brazilian Brahma Chopp beer and guarana soft drinks.

"We went to Rio for carnaval a couple years ago," said Ken Chase of Capitol Hill, in a brilliant orange and yellow flamenco shirt. "It's not very easy to get back each year, so this looks like a pretty good substitute--it brings out the carioca, the craziness in everybody."

Faces in a carnaval crowd: Lucille Guglielmi, a Virginia belly dancer, sheathed in black and red veils and encased in glittering gold coins, swatting dancing males with her tambourine. Penny Turcell, a family therapist from Columbia, in a Technicolor balloon-filled plastic bag and clear face mask. Artist Joanne Kent of Adams-Morgan, a mirage in blue, from her shredded blue dress to her turquoise hair and aquamarine skin. A basketball player in green satin shorts, blowing smoke rings and dancing frantically with a rosary twirling nun. Rhinestone cowboys, Penzance pirates, patriots and Pierrots, women in tuxedos and men in gold eyeshadow and glitter.

Art collector Dan Traub drew gasps and applause for his imposing entrance in a towering green feather headress, silver chest straps and fringed leggings. "This may be the only costume that was actually on the avenue in Rio," boasted Traub, dancing with Marlene Oliveira, a Brazilian employed at the Organization of American States.

"I love it! I want to go to Rio--now!" shouted chic sheik Arthur Froe, a NASA subcontractor, in striped turban and flowing robes.

"My wife is Brazilian," said Harold Motin, a naval engineer and chairman of the carnival committee. "I met her at a friend's birthday party in Washington--he invited me to meet some Brazilian ladies. They're the best," chuckled Motin, as his Brazilian friend, Creusa Leary, tugged him back into the surging samba line. Leary, in a dark rhinestone-drenched dress, later created her own Rio floorshow, cavorting on a tabletop, entwined in bobbing colored balloons and sparkling in the flashbulb bursts.

Late in the evening, Napoleon and his Josephine rumbaed by, perhaps celebrating their last night in Washington. Stuart Nelson, a retired Navy admiral, was every bit the world conqueror, from his high black boots to the spit curl on his forehead. He and his wife, Laura, in tiara and white sequined sheath won second prize for their costumes. Malvina Silva, a Shoreham cafeteria employe who left Brazil for Washington 19 years ago, took first prize in her elaborate lace hoop skirt and Carmen Miranda fruit headdress.