1. Americans for a Better Tomorrow Tomorrow

Stephen Colbert is good at telling jokes, of course, but people are taking his super PAC seriously. Americans for a Better Tomorrow Tomorrow has raised quite a bit of cash and is now under the leadership of Jon Stewart, as Colbert weighs a presidential run in South Carolina. Already, the PAC has cut its first ad—promoting Herman Cain.

2. American Crossroads

Led by Republican strategist Karl Rove, American Crossroads is hoovering up millions of dollars—close to $7 million—in donations to promote GOP candidates this election cycle. The organization is targeting President Obama specifically but is advocating for the defeat of Democrats across the country.

3. Priorities USA

Priorities USA is the Democrats’ answer to American Crossroads, but it is having trouble bringing in the money. The group raised just $5 million during the first six months of 2011. But even if it can’t keep up on the money front, Priorities USA thinks it’s got a winning strategy. It plans to play up Mitt Romney’s harsh immigration rhetoric and the GOP’s embrace of a plan that would gut Medicare as we know it.

4. Majority PAC

So far this election cycle, the Democratic-aligned Majority PAC has raised more than $1 million. The organization has spent roughly half of that to help Democratic senators, including Claire McCaskill, Ben Nelson, and Kent Conrad.

5. Restore Our Future

The pro-Romney super PAC has far and away raised the most campaign cash for the 2012 election, pulling in more than $12 million so far. The group has spent the vast majority of that money tearing down other Republicans to help propel the former Massachusetts governor to the nomination. So far the group has spent more than $10 million on messaging against former House speaker Newt Gingrich and about $400,000 against former senator Rick Santorum.

6. Winning Our Future

The super PAC dedicated to getting Newt Gingrich elected the next president of the United States is off to a good start, raising more than $10 million on the strength of two mega-donations from billionaire Sheldon Adelson and his wife, Miriam. The organization is behind the controversial When Mitt Romney Came to Town video, which highlights the former governor’s tenure at Bain Capital.

7. Make Us Great Again

Rick Perry may no longer be in the hunt for the presidency, but that’s not because the super PAC supporting his bid didn’t try. The group spent almost $4 million to help the Texas governor reach out to potential voters. It also produced some pretty negative ads against Romney and Gingrich, painting the pair as fake conservatives.

8. Endorse Liberty

Endorse Liberty bills itself as a coalition of “entrepreneurs, inventors and creators who have come together to promote the cause of liberty as the founding principle that powers America.” In practice, that means it’s supporting Rep. Ron Paul, the libertarian running for the GOP nomination. To date, the group has spent $3 million to help the former OB/GYN make it to the White House.

9. Strong America Now

Strong America Now has a slogan that’s easy to remember: “No deficit, no new taxes.” The super PAC has graded the Republican candidates on their platforms to eliminate government waste, bestowing A's on Gingrich and Santorum. Paul gets a B, while Romney gets the lowest mark, registering a D for his efforts.

10. House Majority PAC

The Democrats lost 63 House seats in 2010 in a historic election that handed control of the lower chamber to their Republican colleagues. But now the House Majority super PAC is trying to help liberals take back those GOP gains. So far this election season, the organization has spent more than $1.4 million against such high-profile Republicans as Tea Party favorite Rep. Allen West of Florida and Rep. Steve King of Iowa.