From msnbc.com's Carrie Dann and Ryan McCartney:

Washington, D.C. -- It's a crisp, sunny fall day here and thousands are gathering on the National Mall for the Jon Stewart/Stephen Colbert "Rally to Restore Sanity and/or Fear." Since noon, the crowd has been warmed up and entertained by the likes of The Roots, John Legend and the hosts of "Myth Busters."

The crowds stretch for about four blocks at this point with more people streaming in on both sides of the Mall. Unlike the Glenn Beck rally last August (which this one is seen as the counter rally), there are plenty of signs being sported today.

Some examples: A sign in Islamic script with a subtitle reading: "Relax, it just says McDonalds"; another that says "Don't you hate pants?"; another stating "Obama=Keynesian" and plenty of signs targeting Fox News.

Isaac Attias, 23, came from Brooklyn, New York and the recent college graduate wore his cap and gown and carried a sign that says: "Will trade diploma for job." A strict Democrat, Attias says, "I graduated with what I have on. This was the actual cap and gown I wore when I graduated--it served me well for 20 minutes."

Attias and his friend Mike Bradley said they were surprised at the varying ages of the attendees. "A lot of people were saying it was going to be all college-aged kids like us, but there are a lot of older people here."

One of those older attendees was Ramelle MaCoy, 85, who came from Harrisburg Pennsylvania. McCoy carried a sign reading, "Levitate if you think Fox News is fair and balanced."

McCoy said he came to protest the influence of the Tea Party in this election and says he feel confident that this rally will help turn out the vote for Democrats this Tuesday. "I feel confident with no good reason that a large percentage of the massive crowd here will vote and a great percentage will vote for having been here."

Crunched but not confused: From Carrie Dann in the crowd: A block away from the rally, it's tough to see or hear much.

It's packed the point of being difficult to move around, and the acoustics aren't good enough to make out the words coming from the stage. But it's not stopping folks from enjoying the party atmosphere.

People have climbed atop the Porta Potty's and dumpsters in order to get a better view. Folks who have climbed into trees are starting cheers and applause.

"What are we cheering for!?" many ask each other, gleefully cheering along anyway.

Yes, that might be a metaphor: It's more about being a part of the event than the content for the people who have come for the day, it seems.

There's a wide variety of reasons that people are here -- there are plenty of clever signs, a smattering of goofy costumes, and political messages of promoting tolerance and bashing FOX News, Sarah Palin, and the Tea Party -- generally with some tongue-in-cheek humor. ("Don't Tea on My Leg and then tell me it's raining")

But the common thread appears to be annoyance at the shrillness of Tea Party politics, and a general desire to be recognized as reasonable people who care.

"Just chill," is the sentiment of many a sign.

"This is pushback," said Karen, a government employee from southern Maryland who's in her 40s. "Pushback against what the right says about us, about 'business as usual in Washington.'"

This, she says with a grin, is "the political equivalent of Woodstock."

Big names -- from the entertainment world: In case you haven't noticed yet, the theme of this rally is pitting "sanity" (personified by Stewart) against "fear" (in the person of Colbert). Plenty of big name entertainers are on hand to bolster that battle, including a battle of the bands faceoff between Ozzy Osbourne and his hit, "Crazy Train" and Yusuf Islam/Cat Stevens' "Peace Train." In the end, it was settled by the O'Jays and a rendition of "Love Train."

No political figures on stage, at least not yet.

More signage: Some more signs spotted in the crowd:

"I already regret choosing to carry a sign around all day"

"Bipartisanship is sexy"

"Save the dinosaurs"

"In reason we trust"

"I'm not pro-abortion"

"Green Tea Party"

"Vote lawyers out"

"Beck, putting the dumb in freedom"

Bookends: msnbc's Vaughn Ververs weighs in from afar -- There are plenty of differences between this gathering and the Beck rally back in August but also some notable similarities. Neither rally has been overtly political in terms of pushing a specific issue or policy agenda. The first was clearly conservative, this one clearly progressive in nature. Neither has featured elected officials (although Sarah Palin did speak at the Beck rally and she is clearly a political figure).

For a political season centered on anti-establishment sentiment, it's not a surprise we're not seeing a whole bunch of elected officials but both rallies serve to illustrate what can be described as a cultural tug-of-war. Fittingly, Beck held his rally in front of the Lincoln Memorial. Today's rally is at the other end of The Mall, in front of the Capitol. Bookends indeed.

Some final thoughts: From Carrie Dann at The Mall -- This may have been the only rally in American history attended by tens of thousands of irony-loving hipsters, Democratic-leaning middle-aged federal workers, a rap-star-turned-country-singer, libertarian pot legalization activists, a butter-voiced songster, and dozens of people in banana suits.

The "Rally to Restore Sanity and/or Fear" was attended by tens of thousands of supporters of comedians/satirists Stewart and Colbert -- ranging from families who had traveled cross-country to attend to curious locals. The size of the event appeared fairly comparable to the Beck rally, but the atmosphere of this event was less Fourth of July than it was Halloween, New Years, the Fourth of July, and a rock concert rolled into one.

Signs abounded, as the event's hosts had urged during the run up to the event. The messages ranged from strongly political ("The Left is what's right; The Right is what's left"), to tongue-in-cheek ("Poster board is a terrible medium for complex arguments"), to just plain silly ("Grapes are delicious.")

The carnival atmosphere was enhanced by many attendees who wore Halloween costumes -- there were medieval soldiers, vuvuzelas, cartons of French fries, and Waldos, bananas, and zombies aplenty.

Many of the attendees were able to see very little of the rally. People climbed aboard portable restrooms, dangled from trees, and crowded near the area reserved for media in hopes of catching a glimpse of the stage or an audio feed of Stewart and Colbert's banter and musical performances by the likes of The Roots, Kid Rock, and Tony Bennett.

Their message was mostly one of political moderation, the common humanity of Americans of all different political views, and frustration with the media's portrayal of partisan politics. (A common sign in the crowd: "Think outside the FOX.")

While those with prime seats were rapt listeners to the comedians' sometimes-jokey, sometimes-obliquely-political jokes and observations, those packed onto either side of the mall were a combination of curious people-watchers and those content to feel like the part of a social movement fueled by moderation -- even if the message was hard to hear.

If this and the Beck rally were what the 2010 midterm elections are all about, the 2012 presidential election will be eagerly anticipated.