In the largest spontaneous gathering in Tiananmen Square in a decade, hundreds of thousands of ordinary residents took back the center of their city tonight.

Gone were the goose-stepping soldiers and the squads of farmers, workers and students dancing on cue who starred in Friday's invitation-only official celebration of 50 years of Communist rule. In their place were snuggling lovers, kite fliers and families with children holding Chinese flags.

Authorities had cordoned off downtown Beijing for the Oct. 1 National Day "mass parade" and military review, forcing citizens to watch the regimented anniversary procession of tanks and garish floats on television. The highly political ceremony focused on the army and President Jiang Zemin.

But the cordons came down today, and the masses streamed in to see the bright lights and kitschy floats parked on the massive square, bringing a sense of fun that has been lacking in China's antiseptic birthday bash.

"You can see a lot better than on TV," said Lai Zhenjiang, 58, a retired scissors factory worker who was munching on a traditional moon cake and came with his wife and son. "Yesterday, we couldn't come. . . . Now it's a free activity. No one is controlling us."

The square's usually staid granite expanses were aglow with Christmas lights and green lasers, and the cool fall air was a demolition derby of sounds. Syrupy pop music from Qinghai province's parade float mixed with patriotic opera. Nearby, Mongolian melodies blended with a history lesson blaring from an oversize sedan topped with a crown of spinning fruit, the bizarre parade entry from the auto-producing province of Jilin.

The careful screening of participants for the earlier official celebration also gave way to a more eclectic and relaxed crowd. Couples lounged on the red carpet put out for Friday's military honor guard. An unemployed bus conductor with long hair and earrings confided that he had little use for all the floats.

"They're not good or bad. There's no way to tell them apart," he said.

Not everyone was thrilled with the multitudes on the square.

"It's too crowded, don't you think? Today is for the general public," said university student Wan Anan, 20, who danced in the official ceremony. "Yesterday it was very organized. There was a student section, a peasant section and a worker section."

Police estimates put the size of tonight's crowd in the "hundreds of thousands" and said it was larger than another spontaneous gathering before the handover of Hong Kong in 1997. In 1989, more than a million people headed for the square before the military crushed democracy demonstrations there.

Elsewhere in Beijing today, authorities pushed ahead with the next stage of their official festivities, which will run in 10 parks for several days. Jingshan park hosted a program called "Old and Young Celebrate Together," which featured 13 tuxedo-clad "old comrades" singing a somber Soviet World War II ballad and a Chinese revolutionary war anthem called "Guerrillas' Song" to a group of 75 youngsters penned in by parents sitting in rows around them.

"We chose the songs so the young people will not forget the past," said Ge Zhengsu, 73, a former senior air force officer.

CAPTION: The day after invitation-only 50th anniversary festivities, hundreds of thousands of Chinese crowd Tiananmen Square.