WASHINGTON — It was the morning of President Barack Obama’s inauguration, just past five and still dark, when a tune familiar to all Americans drifted across the National Mall.

The performers, bundled in scarves and hooded sweatshirts and huddled together to stay warm, were not as glamorous and far more sleep-deprived than the high-powered stars who had preceded them at a Lincoln Memorial concert two days earlier. But the growing cluster of people moved in a surprisingly well-choreographed routine.

“You put your whole self in, you put your whole self out,” sang out a group of 20 or so spectators, as they jumped back and forth on the gravel in front of the Smithsonian’s Air and Space Museum. “Oh, no you don’t!” someone else yelled back, clearly displeased with the festivities.

For some, this crowd was growing far too crowded for so much predawn enthusiasm. The temperature was below freezing. Early arrivals to the Mall, hoping to lay claim to the best views of the inauguration ceremony, were surprised to find a flood of like-minded people squeezing through every point of entrance. Yet somehow, several enterprising students from Alabama A & M University had convinced a crowd of complete strangers to join them in a rousing rendition of the “Hokey Pokey,” helping the sleepless stay awake another hour to fight the cold and witness history.

Brandon Lewis, 21, a college senior who had just survived a 14-hour bus ride from Huntsville, Alabama with his classmates, said the sing-along was a pragmatic choice.

“It’s just to keep us together and keep warm. If people start losing each other we just sing,” Lewis said. The music was infectious. Right away, an even larger crowd joined the students as they belted out an especially heartfelt version of “Lean on Me.”

Like many other members of the crowd, Lewis said the cold and discomfort he would feel for the next hours was a small price to pay for an experience he would remember for the rest of his life. “I just want to be here,” said Lewis, who is African-American. “I look at it now like the sky’s the limit. Barack Obama’s president, you can do anything. It made me want to go after my dreams.”

Sandy Abramson, 50, a psychologist, drove 10 hours from Boston with her 13-year-old son Louie to witness Obama’s inauguration. Asked whether she believed that Obama would bring America out of its current crisis, Abramson responded, “I know it’s not gonna happen fast, but I feel like it is gonna happen.” Looking around her at the crowd, Abramson added, “I’ve been here so many times but this is just the most amazing thing. I feel hopeful.”

Irene Jagla, 24, a graduate student at Georgetown University, said she was proud to be part of the shivering masses as Obama’s inauguration day dawned. Looking at the thousands who had crowded the Mall well before six in the morning, she could scarcely contain her enthusiasm. “I wanted to be part of the biggest thing that will happen in my lifetime. There’s a huge sense of unity and of everyone being in it together. It’s crazy. It’s really the biggest thing I’ve ever been a part of,” Jagla said.

“And it’s freezing,” she added, smiling. “But I’m not going to complain.”