They sang the National Anthem in Fayetteville, N.C., marched through the streets in Eustis, Fla., and wore colonial outfits on Boston Common, not far from the original Boston Tea Party.
In Montgomery, Ala., more than 1,000 marched on the State House. Some carried signs warning the country was on the path to socialism. In Cincinnati an estimated 4,000 people delivered a petition demanding officials reject federal stimulus money.
In Washington today, a crowd of protesters forced a temporary shutdown of the White House when they hurled tea bags onto the executive mansion's lawn.
It's all part of a nationwide series of demonstrations to protest tax hikes and massive government spending in the wake of the U.S. recession.
Chandler Ramelle, an organizer of the otherwise peaceful D.C. protests told ABC News Radio Network, "we're not rioting, nobody wants to do that, we just want to be heard and want you to know that we're concerned."
"Without Facebook and Twitter and the blogs that have been so active in this, there's no way that this kind of event could have been organized in the size and the scope that it has been," said Smart Girl Politics' Katie Favazza today on "Top Line." Favazza helped bring people together today for the Washington, D.C. event across from the White House.
More than 750 events across all 50 states were planned for today, with organizers in several larger cities predicting attendance in the tens of thousands to protest high taxes and rising government spending.
The events have come together in less than two months' time, after a CNBC personality suggested that angry citizens protest the Obama administration's approach to the economic crisis by channeling the spirit of protest that sparked the Boston Tea Party.
If crowds approach their predicted levels, it will be an impressive display of grassroots activism -- on a scale rarely, if ever, demonstrated by conservatives.
Although there's been little advertising and no real top-down direction from party leaders, they've made extensive use of social networking sites to bring activists together.
"This could be the beginning of conservative online grassroots politics," said David All, a Republican Internet strategist. "It has real potential. The interesting thing will be to see how it pivots, and whether it pivots. The real question is what happens after April 15."
The explosion of interest has left some conservative strategists wondering whether the Republican Party might have stumbled across the makings of its own version of the liberal MoveOn.org -- a powerful organization with the ability to shape national politics.
Others caution not to overestimate the tea parties' impact.
Air America national correspondent Ana Marie Cox said today on "Top Line" that while it's good that the rallies are bringing people together, "I just think that we should not confuse, like, this outpouring with something that is a huge movement."
And while the Boston Tea Party in 1773 was about taxation without representation, some point out that today's protesters did get to vote. They just lost.
"The thing is, the Progressives won," Cox said. "I mean, there's not a lot of like counter protest to these tea parties because the stimulus bill passed, you know."
But even if the numbers match elevated expectations, questions are swirling around what's next for the activists.
The movement is leaderless and only aligns indirectly with party politics. While many participants will be Republicans, the anti-spending message is more closely aligned with libertarian themes of small government, with many people angry at both Democrats and Republicans.
"These are folks who have never been involved in the political process before," said Eric Odom, who designed and is running two Web sites to connect supporters and corral information about the protests. Odom said he supported Libertarian Bob Barr for president last year.
"This is a birth of a completely new movement, with a new face, that hasn't been seen anywhere in the country," Odom said.
The question of what to do with the organizing energy will hover over the day's events.
"It's a good and complicated question. When you have a citizen movement, who moves the citizens?" said Roger L. Simon, who has helped spread word of the protests through his Web site Pajamas Media.
Regardless of what happens, the tea parties have made a mark. Fox News Channel has joined conservative bloggers and radio hosts in promoting the events for weeks; Fox is planning several hours of live coverage at different sites around the country today.
At the White House Tuesday, Press Secretary Robert Gibbs said he wasn't sure if Obama was aware of the tea parties but said the president would be using the April 15 tax filing deadline to make a point of his own.
"I think the president will use tomorrow as a day to have an event here at the White House to signal the important steps in the economic recovery and reinvestment plan that cut taxes for 95 percent of working families in America, just as the president proposed doing, cuts in taxes and tax credits for the creation of clean energy jobs," Gibbs said.
It all began with a televised rant by CNBC's Rick Santelli Feb. 19. From the floor of the Chicago Mercantile Exchange, Santelli drew cheers from traders as he attacked the president's plan to prop up mortgages and suggested that he and others dump "derivative securities" into Lake Michigan in a "Chicago Tea Party."
The concept quickly spread among grassroots activists, helped along by conservative bloggers and others who connected via social networking sites. As the idea took hold, organizers turned down offers of organizational support from the Republican National Committee.
"Believe me -- this is not Republican-inspired. This is just people," said Pat Longo, a Republican national committeewoman from Connecticut. She was urging people to attend events in her state but had nothing to do with pulling them together.
In Dayton, Ohio, for instance, the speakers include a retired clinical psychologist, the wife of an Air Force officer, the 74-year old owner of a tobacco business and other local small business owners -- not a slate of elected officials.
"I did not want to make it, 'Let's get a congressman up there, let's get a senator up there,'" said Rob Scott said, a University of Dayton law student who is helping organize the event. "People are tired of that."
Still, national Republicans are embracing the concept: House Minority Leader John Boehner, R-Ohio, is attending a "tea party" event in California, and numerous Republican members of Congress are doing the same in their districts.
Michael Steele, the Republican National Committee chairman, on Tuesday sent an e-mail to supporters inviting them so submit "virtual tea bags" to Democratic leaders in Congress.
But even as the message is heard in Washington, many inside the GOP aren't quite sure what to make of the protests. While participants are expecting to be largely supportive of Republican causes, the events are being fueled by an anti-incumbent sentiment that may not respect party lines.
"Participation here across the country has much more to do with this very vocal sector of the electorate that is really, really fed up with the status quo in Washington," Kevin Madden, a Republican consultant, said on ABCNews.com's "Top Line" Tuesday.
"It's almost libertarian more than it is Republican or Democrat," Madden said. "These are instead very grassroots-driven, against Washington and against both parties."
Speaking Tuesday at the National Press Club, Grover Norquist, the president of Americans for Tax Reform, sought to distinguish the tea parties from tax revolts of the past.
"In the past, taxpayer activism has come because taxes were raised last week," said Norquist. "The rallies that have been going on for the last month or so … are not in reaction to a particular tax increase. They're in reaction to a government explosion of spending which people recognize will lead to higher taxes and probably inflation down the road."
Norquist was scheduled to speak at a tea party in the Washington, D.C., area, but he was not one of the organizers.
Some in the Republican party are hesitant to read too much into the events. This is just one attempt at a new kind of organizing by conservatives, but by no means will it be the last, said GOP consultant Phil Musser.
"I'm not sure if this is the full-blown test of the strength of the 'Netroots' of the right. But it's an important demonstration: Republicans have begun to recognize and use the social networking sites used by the Obama campaign," Musser said. "It will be fun to watch."
Already, organizers are making plans for what's next. Talk has begun of candidate recruitment for state and local races. Activists are planning for fights over state budgets from California to Connecticut. Another nationwide event -- scheduled for July 4 -- is already in the works.
Odom said he hopes and trusts activists will stay in touch to figure out among themselves how to harness the organizing tools they're honing.
"We're pretty confident that, post-April 15, there will be a plethora of new networks and organizations that develop organically," he said.
For a day, at least, it promises to produce quite a scene.
"We just want to show that the silent majority has a face," said Corie Whalen, a senior at Simmons College, who is helping to organize the event in Boston.
"We definitely have people that are going to come dressed in historical costume," Whalen added. "People are definitely bringing tea."
The Associated Press and ABC News' Teddy Davis and Ferdous Al-Faruque contributed to this report.