DENVER - From the time Howard Dean banged the gavel three times to a mostly empty arena Monday afternoon to the crowds cheering Michelle Obama's nighttime speech, the first day of the convention was a spectacle.

Thousands of delegates, along with media and guests, packed Denver's Pepsi Center for the Democratic National Convention on Monday.

During the day, the mood was decidedly casual. Spotlights scanning the crowds almost made it feel more like a dance club than a political gathering, at times. Around 4 p.m., over by the Florida delegation, several beach balls started to be batted around.

People wandered the floor and chatted during the afternoon speeches, but the atmosphere was more charged by the time the evening's program began.

The crowd went wild for Jimmy Carter, who made an appearance but did not speak after a video focusing on efforts to rebuild New Orleans.

Later on, Sen. Edward Kennedy, who has brain cancer, spoke to an arena that was bursting with waving Kennedy signs.

"My fellow Democrats, my fellow Americans, it is so wonderful to be here," Kennedy said. "Nothing, nothing was going to keep me away from this special gathering tonight."

Kennedy didn't hesitate to draw comparisons between the goals of Obama and the achievements of his brother, John F. Kennedy.

"We reach the moon, and we scale the heights. I know it, I've seen it, I've lived it, and we can do it again," Kennedy said. "The work begins anew, the hope rises again, and the dream lives on."

During the proceedings, when a state's name was mentioned that section would erupt in cheers. Monday was heavy with speakers from Illinois, but Wisconsin will get a share of the spotlight today when Gov. Jim Doyle speaks.

Lt. Gov. Barbara Lawton, sitting with the Wisconsin delegation Monday, said she didn't know if Doyle had been asked to speak on a specific topic. But, she said, if Doyle speaks about the importance of Sen. Barack Obama to Wisconsin, he could discuss what he would do for the economy, health care reform, creating jobs and higher education.

"We need a partner for that, and the only hope for change from the last eight years," Lawton said, "that's Barack Obama."

If Obama was the must-mention of the evening, a strong undercurrent was the importance of unity.

"As Democrats, the moments that make us most proud are those when we unite to find common ground," said Judith McHale, co-chair of the platform committee.

McHale mentioned both Sen. Hillary Clinton and Obama in her speech, to scattered applause for each.

Some of the biggest cheers of the night were saved for last, as the arena loudly welcomed Michelle Obama, rising out of their seats and holding vertical "Michelle" signs. Obama spent her speech discussing her family and her husband, and also giving credit to Clinton for gaining 18 million votes. She ended her speech with a call to action for the election.

"Tonight, in honor of my father's memory and my daughters' future, out of gratitude for those whose triumphs we mark this week and those whose everyday sacrifices have brought us to this moment," Obama said, "let us devote ourselves to finishing their work."