They are hundreds strong, but the protesters calling themselves Occupy Wall Street claim to speak for millions.
"It's about democracy; it's about everyone here has a chance to speak and be heard," said Justin Brown of Brooklyn, who joined the protest a week ago.
Their causes include everything from global warming to gas prices to corporate greed, and the Occupy Wall Street website says organizers took their inspiration in part from the so-called Arab Spring demonstrations that have tried to bring democracy across the Arab world.
But while their message might be a tad muddled, all are united by their anger over what they say is a broken system, a system that serves the wealthy and powerful at the expense of the rest.
Protester Brendan Burke insists he and the others are fighting for more than 99 percent of the American population.
"Everyone has this problem," he said, "White, black. Rich or poor. Where you live. Everyone has a financial inequity oppressing them."
Few had heard of Occupy Wall Street two weeks ago when protesters moved into a park in the heart of New York's financial district.
But after 15 straight days, they are now getting the backing of prominent celebrities like documentary film maker Michael Moore and Oscar-winning actress Susan Sarandon.
They're also now backed by powerful labor unions with hundreds of thousands of members and millions of dollars behind them.
Sympathetic protests are popping up in other cities, including Los Angeles; Boston; Washington; Providence, R.I.; Albuquerque, N.M.; and Spokane, Wash., with many demonstrations taking place Saturday.
Columbia University political science professor Dorian Warren said he thinks the protests could continue to grow.
"The country as a whole is not happy," Warren said. "Eight out of 10 Americans are not satisfied with the direction of the country. So they're just expressing what people have been saying."
The protesters call their block of Lower Manhattan "Liberty Square" and it has been their around-the-clock home for two weeks. It's a little city unto itself with a media center and library, a kitchen -- even a medical clinic.
The square has a bit of 1960s vibe, complete with folk guitarists, tie-dye clothing and communal living.
The protesters are getting the word out through social media and their very own newspaper, The Occupied Wall Street Journal.
The majority are under 30, but they are activists of every age. Catharine Revland has been taking part in protests since 1963.
"Every demonstration starts with being ignored," she said. "Then sneered at. Then hated. Then finally: they get the message."
The protests have been mostly peaceful. That is, until Saturday, when 700 were arrested after a march on the Brooklyn Bridge spilled over from the pedestrian walkway onto the roadway, blocking traffic for several hours. Most of the demonstrators who were arrested were given a summonses and released.
"The key thing about any movement is that it gets issues on the agenda that the political parties don't want to deal with," Warren said.
While they may have a ways to go before attaining tea party-like influence, Occupy Wall Street backers say they hope their message will continue to gain momentum -- and will ultimately be heard in the 2012 elections.
In fact, some tea party members have been down to Liberty Square to lend their support. Both groups are fed up with the status quo.
Still, the protesters insist they are not all Democrats nor Republicans.
"We're Americans," said Justin Brown.