Costumed as giant rabbits or walking raisins, as politicians, nerds or visitors from space, as well as the more traditional witches, ghouls and monsters, tens of thousands of people filled the streets of Georgetown last night in a boisterously high-spirited celebration of Halloween.

Amid blaring music and exuberant shouting and a certain amount of pushing and shoving, the revelers -- many in elaborate makeup, a number wearing Ronald Reagan masks, six representing a six-pack of beer, one portraying a gasoline pump -- joined others in everyday attire in making their way up and down streets that were closed to traffic for the night's festivities.

"Everybody's checking out everybody else's costume," said Ephraim Massasseh, a cook at Swensen's Ice Cream on Wisconsin Avenue NW.

Police estimated the crowd at 150,000 and said good weather helped boost the turnout over last year's 100,000.

By midnight police had reported 13 arrests. At least three came after helmeted officers attempted to quell an outbreak of unruliness at Wisconsin Avenue and M Street, the focus of the night's festivities.

Earlier, police said, one person was arrested on a purse snatching charge and several were charged with disorderly conduct. One man was arrested on a charge of receiving stolen property after he was spotted wearing an officer's cap, police said.

Two persons were reported injured. One had a seizure and another, a motorcycle passenger, struck her knee against a taxicab door that had just been opened.

Elsewhere in the city and suburbs there were no immediate reports of arrests or injuries in connection with Halloween celebrations.

While Georgetown's streets and sidewalks were jammed with a walking, standing and shoving inventory of Washington's attics, costume shops and creative imagination, in many of the neighborhood's bars and restaurants, the scene seemed very much the same.

Annie's on M Street was packed, with "a lot of devils, a lot of werewolves, and a space couple from the planet Mars," said employe Steve Shealy.

At the Roy Rogers on Wisconsin Avenue, a couple of Draculas forsook their usual diet of blood to dine on chicken, an employe reported. Patrons at J Pauls shouted, applauded and demanded a speech from a man who entered in a Richard Nixon mask. Revelers garbed as nuns ate pizza at Ikaros.

Costumes were much in evidence at the Little Tavern at 1301 Wisconsin Ave., but there was "no celebration," said employe Carolyn Edwards. Customers, who she said came in guises that ran the gamut from "mummies to . . . everything," were "buying a lot of hamburgers . . . {but} just not tipping."

Outside, beginning in early evening and continuing early today, it was the bizarre, the macabre and the unexpected. Sherlock Holmes accompanied a witch. Three men in coveralls said they were playing the role of nuclear waste. Richard Fitzgerald, 50, was rigged out as a gasoline pump. Attached to him was his wife Jackie, 42, who was outfitted as a car.

Two couples came as walking raisins, in imitation of a television commercial. The raisin effect was created by trashbags, stuffed with newspapers and worn about their bodies.

Wendi Warner, one of the four, claimed to be miffed because the male members of the group "think we're garbage."

Some merrymakers seemed to have their innards painted on the exteriors of their costumes. Some were dressed for jungle combat. One man wore only a diaper.

Bryan Heiser, 19, whose costume made him appear hideously mutilated, explained that "this is what happens after nuclear war."

Two men who insisted that their names were Gilbert and Philbert Nostril said they represented nerds, and they wore costumes that included white socks and high water pants -- trousers with bottoms that ended well above their shoetops.

One of them said that the trousers were so tailored "in case it rains really hard."

Decked out as a monster, Ron Lara, 43, a financial analyst from Reston, explained what led him to join the frenzied throng. "It's just the kid in me, I guess," he told a reporter.

In the mischievous spirit of the evening, his daughter, Carrie, 13, tried to undercut his explanation. "He goes out every night like this," she said.

Elaborating on the reasons for his get-up, Lara cited the stock market crash. In its aftermath, he said, "I thought I'd find another way to meet clients."

The crowd, which included a number of men in women's garb, appeared to amaze, bemuse and bewilder some onlookers. One, Gin Yuan, who said he is a visitor from China, told a reporter that "there's nothing like this" in his country. A visitor from Sudan, who gave his last name as Bushka but declined to give a first name, delivered a similar verdict:

"I don't know whether it is something fun, something good or something strange -- very, very strange," he said.

Staff writer Carlos Sanchez contributed to this report.