"We live now in hard times," Stewart said after all the shtick. "Not end times."
Part comedy show, part pep talk, the rally drew together tens of thousands stretched across an expanse of the National Mall, a festive congregation of the goofy and the politically disenchanted. People carried signs merrily protesting the existence of protest signs. Some dressed like bananas, wizards, Martians and Uncle Sam.
Stewart, a satirist who makes his living skewering the famous, came to play nice. He decried the "extensive effort it takes to hate" and declared "we can have animus and not be enemies."
Screens showed a variety of pundits and politicians from the left and right, engaged in divisive rhetoric. Prominently shown: Glenn Beck, whose conservative Restoring Honor rally in Washington in August was part of the motivation for the Stewart and Colbert event, called the Rally to Restore Sanity and/or Fear. It appeared to rival Beck's rally in attendance.
Colbert, who poses as an ultraconservative on his show, played the personification of fear at the rally. He arrived on stage in a capsule like a rescued Chilean miner, from a supposed underground bunker. He pretended to distrust all Muslims until one of his heroes, basketball great Kareem Abdul-Jabbar, who is Muslim, came on the stage.
"Maybe I need to be more discerning," Colbert mused. He told Stewart: "Your reasonableness is poisoning my fear."
As part of the comedic routine, Stewart and his associates asked some in the audience to identify themselves by category, eliciting answers such as "half-Mexican, half-white," "American woman single" and "Asian-American from Taiwan."
"It's a perfect demographic sampling of the American people," Stewart cracked to a crowd filled with mostly younger whites. "As you know, if you have too many white people at a rally, your cause is racist. If you have too many people of color, then you must be asking for something - special rights, like eating at restaurants or piggy back rides."
With critical congressional elections looming Tuesday, Stewart and Colbert refrained from taking political sides on stage, even as many in the crowd wore T-shirts that read "Stewart-Colbert 2012" and left-leaning advocacy groups set up shop on the periphery, hoping to draw people to their causes of gay rights, marijuana legalization, abortion rights and more.
Organizing for America, Obama's political operation based at Democratic National Committee headquarters, was mounting a "Phone Bank for Sanity" to urge people to vote Tuesday.
Stewart sang along as Jeff Tweedy sang that America "is the greatest, strongest country in the world. There is no one more American than we."
Kid Rock and Sheryl Crow also performed, singing if "I can't change the world to make it better, the least I can do is care." Ozzy Osbourne and Yusuf Islam, formerly known as Cat Stevens, engaged in something of a battle of the bands as the heavy-metal rocker barged in on the folkie's hit, "Peace Train," in a mock clash of music and cultures. Tony Bennett closed the show by singing "America the Beautiful."
The idea was to provide a counterweight to all the shouting and flying insults of these polarized times. But there were political undertones, too, pushing back against conservatives ahead of Tuesday's election.
Slogans urged people to "relax." But also: "Righties, don't stomp on my head," a reference to a Republican rally in Kentucky at which a liberal activist was pulled to the ground and stepped on. And, "I wouldn't care if the president was Muslim."
Shannon Escobar, 31, of Bangor, Pa., came with a group of 400 people on buses chartered in New York. A supporter of President Barack Obama in 2008, she said she's tired of nasty rhetoric from both sides and disenchanted with lack of progress in Washington.
"I want to see real change - not Obama change," she said. "We need a clean slate and start over with people really working together."
A regular viewer of Stewart's "The Daily Show," she said she had a dream that he ran for political office, but got "corrupt and dirty."
"I need him to stay pure," she said, deadpan. Stewart is popular with Democrats and independents, a Pew Research Center poll found. The stage featured entertainers associated with Democratic causes or Obama's 2008 campaign, but no political sermons from them.
Stewart said the day was about toning down anger, partisan division and shouting.
"If we amplify everything," he said, "we hear nothing." Many of the attendees, sporting stickers that read "Vote Sanity," said they enjoyed the rally's positive message, even if the program ultimately stuck mostly to entertainment. In the days leading to the event, organizers had refused to release a full schedule of speakers, leaving fans uncertain about what to expect.
"I thought it was awesome, with good music. We came for a rally to restore sanity, and that's what we got," said Joe Stroup, 31, of Portland, Ore. "But is it going to bring lasting change? I doubt it."
Comedy Central's park permit anticipated a crowd estimated in advance at 60,000.