Ever-growing crowds thronged to the capital city on the eve of Obama's elevation to the presidency. "Tomorrow, we will come together as one people on the same Mall where Dr. King's dream echoes still," Obama said.
A day away from becoming the nation's 44th president, Obama visited 14 injured vets from Iraq and Afghanistan at Walter Reed Army Medical Center.
Then he visited Sasha Bruce House, a shelter for homeless teens in the District of Columbia, chatting with volunteers who were helping to repaint rooms and then pitching in himself.
"We can't allow any idle hands. Everybody's got to be involved," Obama said. "I think the American people are ready to do that."
Obama, whose presidential campaign made extensive use of the Internet to rally support and gather contributions, said, "The Internet is an amazing tool for us to be able to organize people together. We saw that in our campaign. But we don't just want to use if for winning elections; we want to use it for rebuilding America."
"Don't underestimate the power for people to join together to accomplish amazing things," Obama said.
As to his own painting efforts, Obama said: "I think I've got this wall covered." He once was immersed in such work as a community organizer in Chicago.
Michelle Obama and Vice President-elect Joe Biden's wife, Jill, were visiting RFK Stadium where people were at work wrapping care packages and writing letters to troops overseas.
On the National Mall, a party atmosphere was already evident by midday even though it had started snowing. Several of the large-screen televisions had begun rebroadcasting Sunday afternoon's concert, while in a corner near the Smithsonian Air and Space Museum, the Boy's Choir of Kenya performed an impromptu selection for the crowd.
At the Capitol, hundreds of people pressed up against the blocked-off seating area in hopes of getting as close to the inaugural stage as possible.
"Everybody's excited," said Donald Butler, 20, a student at the University of Washington. "There are smiling faces everywhere, and it's a nice, diverse crowd. It's history. I didn't think I would see a black president in my generation. I just had to be here."
President George W. Bush, with just a day left in his term, made phone calls from the White House to Russian Prime Minister Vladimir Putin and a dozen other world leaders to thank them for their work with him over the last eight years. Defense Secretary Robert Gates, meanwhile, was designated by the Bush administration to stay away from Tuesday's inaugural festivities "in order to ensure continuity of government," said Bush spokeswoman Dana Perino.
One official traditionally stays away when others in the line of presidential succession are gathered together, in case of a calamitous attack.
On the streets, live news broadcasts displayed on large-screen televisions attracted swarms of onlookers, and behind the scenes people made final preparations for a slew of parties, balls and other celebrations that will follow Obama's oath-taking and the inaugural parade.
Obama and Biden, fresh off a rollicking concert at the Lincoln Memorial on Sunday, were spending their final day before the inauguration with activities keyed to the celebration of King's life, cut short by an assassin's bullet in 1968.
"Today, we celebrate the life of a preacher who, more than 45 years ago, stood on our National Mall in the shadow of Lincoln and shared his dream for our nation. His was a vision that all Americans might share the freedom to make of our lives what we will; that our children might climb higher than we would," Obama said in a statement.
Obama said King's "was a life lived in loving service to others."
Meanwhile, two wreaths were erected at the future site of the Dr. Martin Luther King Jr. Memorial on the Tidal Basin between the Jefferson Memorial and the Lincoln Memorial. Groups of school children gathered around retired teacher Kirk Moses as he talked about King's legacy of nonviolence and the civil rights leader's connection to Obama.
"The cadence and syntax of Obama, it comes directly from Dr. King," said Moses, 60, as his group took pictures of the bronze plaque that sits where the memorial will be built.
The run-up to Obama's inauguration, like his election itself, has been defined by enormous public enthusiasm, carefully choreographed events and a lofty spirit of unity. What awaits, as Obama often reminds the nation, is many months, if not years, of tough work.
The weekend celebrations began Saturday with Obama's whistle-stop tour, from Philadelphia to Washington, along the path Abraham Lincoln took in 1861. Then came the roaring celebrity-filled concert where several hundred thousand people flanked the Reflecting Pool, hearing actors, singers and then Obama himself rally for national renewal.
The Presidential Inaugural Committee has launched a Web site, USAService.org, to help people find volunteer opportunities close to their homes.
The president-elect scheduled a busy Monday evening, too.
He was to attend three private dinners to honor former Secretary of State Colin Powell; Biden, a longtime senator from Delaware, and Sen. John McCain, the 2008 Republican presidential nominee.
Michelle Obama, the future first lady, was hosting a children's evening concert.
Runner Kim Person stopped in front of the Capitol to snap a few quick pictures of the reviewing stand during a break in her marathon training. Person doesn't have a ticket to the festivities, so she used the early morning lull to get close to the building.
"That's why I'm looking at it today, because I won't be able to see it tomorrow," said Person, 43, who plans to be near the Washington Monument on Tuesday.
Associated Press Writers Jesse Holland and Charles Babington contributed to this report.
On the Net:
Renew America Together: http://usaservice.org/