(CNN) -

"Saturday Night Live" had some fun recently at the expense of undecided voters. Bill Maher took it a step further on his HBO show "Real Time," calling those who have yet to make up their minds in the presidential election "ignorant."

The jokes may be funny, but both campaigns are taking the final phase of the election season very seriously.

The stakes are high in the first debate between President Obama and Mitt Romney, set for Wednesday night in Denver. As New Jersey Gov. Chris Christie said so aptly over the weekend, "This whole race is going to be turned upside down come Thursday morning."

That's not just Jersey bluster. Both Obama and Romney are hoping to land a knockout punch -- a moment where they can break through for good. For viewers everywhere, expect great drama.

Undecideds

The notion that the final month of the election may not matter is, well, ignorant. Presidential debates can make a difference.

Let's look back to 2000. The final debate was "enough to turn a neck-and-neck race into a solid lead for GOP Texas Gov. George W. Bush" over Al Gore.

What did it?

"The debate appears to have made Republicans more enthusiastic about voting while turning some Democrats away from the polls," according to a CNN poll at the time.

Same thing in 2004. After the second presidential debate of the cycle, CNN wrote that Massachusetts Sen. John Kerry "appears to be holding the ground he gained against President Bush after the first presidential debate." It tightened a race that was at one point looking like a Bush runaway. (True, Bush won most of electoral votes, but the difference in popular votes was within 3 percentage points.)

Maher and SNL can poke fun at the undecided voters, but these people matter -- especially in a tight race like the one between Obama and Romney -- since they make up a small but solid percentage of the electorate.

The undecideds will have three more chances to make a decision, including a debate on October 16 that will be moderated by "State of the Union" anchor Candy Crowley.

Unsatisfieds

Recently, 40% of Americans "say they are not too or not at all satisfied, marking the lowest level of candidate satisfaction since the 1992 presidential election." That's a lot of Americans who aren't ready to enthusiastically embrace a candidate or start convincing their friends that their choice is the right one.

What about the last presidential election? In 2008, 72% of voters said they were satisfied with the choices, perhaps because both Barack Obama and Sarah Palin were dynamic.

What does this mean for 2012? Namely, that a big voting bloc is waiting for the candidates to prove their worth.

The unsatisfieds are voters who feel their needs are not being met by the campaign stump speeches and talking points. CNN's Halimah Abdullah took a look at these "slivers" of voters. Abdullah profiled a man who voted for Obama in 2008 but has grown disillusioned. This man has a specific list of items that he finds politically appealing, but neither campaign has satisfied him so far. He plans to tune in to the debates which may sway him.

Late deciders

Like the unsatisfied voters, there is a group of voters who haven't started to pay attention to the race.

They're not glued to the 24-hour news cycle of cable TV or the blogosphere. They're not remotely as invested as the inside-the-beltway crowd. But they do vote, and the debates are a critical last-minute stop for them.

In the 2004 election, which at first looked like a big Bush victory before the debates in the last month, 10% of voters said they decided in the final 30 days, and Kerry captured 54% to Bush's 44% of this group.

Similarly, in the 2008 race, 15% of the voters made their decision in the last month, with more than 50% going for Obama. In 1996, Clinton received more of the last-minute deciders.

Persuadables

There's one more category of people who Obama and Romney will be looking to lock up during the debates. These are the persuadable voters.

They are voters who lean one way or the other but aren't sure whether they will cast a ballot.