Undated (AP) _ Trick-or-treaters traipsed through a Nebraska zoo and costumed marchers frolicked in New York's Greenwich Village parade, but Los Angeles' traditional Halloween street party turned into a late-night melee.

Revelers broke windows and looted stores after police closed Hollywood Boulevard on Monday night to an estimated 100,000 people cruising up and down the packed street, authorities said today.

''We're trying to take the streets back,'' Officer Fritz McDowell said around midnight, about midway through the four-hour melee during which rocks and bottles were thrown. About 150 officers, including some in riot gear and others on horseback, were summoned to quell the disturbance that quickly spread across a 10-block area.

At least 10 businesses were vandalized. Twenty-three people among the estimated 200 who took part in the melee were arrested on a variety of misdemeanor and felony charges, said police Sgt. Ruben Whittington.

There was no indication how many revelers may have been hurt. Three police officers were injured, but none required hospitalization, authorities said.

Elsewhere, about 2,500 people attended a non-alcoholic Halloween party at the University of Wisconsin Field House in Madison while about 20,000 others roamed a city street, site of the traditional bash.

The 20,000 were there despite the fact that the State Street party, which has drawn an up to 100,000 in past Halloweens, was canceled this year because of costs, the need for liability insurance and the 21-year-old drinking age.

In New York, a group of magicians gathered Monday at the grave of magician Harry Houdini for the 62nd Halloween since Houdini's death on Oct. 31, 1926.

At 1:26 p.m. - when Houdini died - a magic wand was snapped in two. But Houdini once again failed to keep his promise to communicate from beyond the grave.

Later in the day, Batman and Robin, Sonny and Cher, and scores of other costumed characters marched through the streets in the city's annual Greenwich Village Halloween Parade.

''This is New York's answer to the Mardi Gras,'' said Jay Raetz, who came in from Ridgewood, N.J., with his family to watch the festivities.

About 250,000 people turned out for the event, police estimated.

Among the marchers was a young woman dressed as Miss Jersey Shore, who wore a huge syringe that appeared to pierce her head in ''tribute'' to the medical waste that closed New Jersey beaches last summer.

That New York staple, Chinese takeout food, was portrayed by a group who appeared as a box of rice, soy sauce, a fortune cookie and a tea bag.

Monday was the final day of a four-day ''Halloween Spooktacular'' at the Riverside Zoo in Scottsbluff, Neb. The zoo was decorated with more than 700 pumpkins, and trick-or-treat stands handed out candy donated by merchants.

''It's unbelievable,'' said Trudy Mann of Scottsbluff, who toured the zoo with her husband, Bill, and their two children.

In Saddle River, N.J., more than 800 costumed children and their parents posed for photos and shook hands with former President Nixon at what has become a Halloween neighborhood ritual.

Crowds bantered and exchanged gifts with Nixon for three hours outside his house in Saddle River, where he has lived since 1981.

Nixon, 75, complimented children on their costumes and passed out more than 700 cards he had personally autographed Monday afternoon.

''Fortunately, I have a short name,'' he said. His grandson, Christopher Cox, 9, stood by to count the guests.

Joanne Carson played hostess in Bel-Air, Calif., to a celebrity holiday bash in honor of the late Truman Capote.

Capote died in Ms. Carson's home in August 1984. She said she promised the author that she would one day throw a West Coast version of his famous annual masked ball at New York's Plaza Hotel.

In Saratoga, Calif., Lise Dominique and Steve Bauer dressed up as cows for a Halloween wedding and said, ''I moo.''

Dominique originally ordered the cow costumes in August as a joke, not for a wedding. The costumes didn't arrive and last month Dominique called the company and insisted she needed them right away because she planned to get married in them on Halloween.

The company apologized and rushed the costumes to Dominique by air freight. All they asked in return were pictures of the cow vows.

Dominique and Bauer, who have lived together for the past 10 years, decided to go through with a wedding rather than admit they'd lied to the company.

''We'd been living together for so long and we needed a nudge,'' said Bauer.