WASHINGTON, D.C. -- On a day that President-elect Barack Obama has dedicated to service, it's fitting that we're sitting on a bleacher in the packed high school auditorium. And, on a day celebrating the legacy of Martin Luther King Jr., it's also fitting to be in Ward 8, D.C.'s southernmost -- and perhaps toughest -- neighborhood, listening to Martin Luther King III remind the packed house about his father's famous call to arms: "Everybody can be great, because everybody can serve."

The words, as always, are inspirational. But on this day -- one MLK III said his father and mother never imagined their country would dedicate to its most famous civil-rights leader -- it's especially moving for a son of greatness to see how his father's call to service has been heeded.

Fittingly, that's also the theme of ServiceNation's "New Era of Service" breakfast at Ballou Senior High School. The event featured civil-rights advocate Congressman John Lewis, California First Lady Maria Shriver and celebrities including Demi Moore, Ashton Kutcher and Tobey Maguire. Lewis stirred the crowd with a fiery speech about taking part in the MLK-led March on Washington in 1961, the year Barack Obama was born.

"Do what you can, what you must to make our country what it should be," he said, adding that he shed so many tears on the night of the election that he didn't know if he would have any left for Tuesday's inauguration.

Lewis' words were so moving that when Maguire, the chair of ServiceNation's Ambassador's Council, took the stage a few moments later, he was clearly awestruck. "I didn't realize this would be such an emotional morning," the "Spider-Man" star said, pausing to collect himself for several seconds. "I'm really humbled to be here."

He was followed by Kutcher and Moore, who unveiled their "Presidential Pledge" Web video. In it, the two, along with Cameron Diaz, Nicole Richie, Ashlee Simpson, Eva Longoria, Eva Mendes and Diddy, make a candid call to action: What's your pledge?

After the program, hundreds of volunteers, students and parents made their way down the hill to start a day of work painting and refurbishing Simon Elementary School.

"Be the Change: Live From the Inaugural" will air live on MTV on Tuesday, January 20, at 10 p.m. ET/ 7 p.m. PT. MTV News will have wall-to-wall coverage of the event and of the scenes in Washington, D.C., New Orleans and Kenya in the days leading up to the event and in the days that follow.