Republican presidential candidate Arizona Senator John McCain speaks during the Town Hall Presidential Debate between Obama and McCain at Belmont University's Curb Event Center October 7, 2008 in Nashville, Tennessee. - 

Tonight the vice presidential candidates will debate at 9 pm Eastern, but the next big presidential debate takes place October 16th. Next week's square-off will be a little bit different, it's a town hall that will put the candidates face-to-face with an audience of 84 voters. Who are these lucky 84 and where do they come from? 

The first presidential town hall debate was at University of Richmond back in 1992 with President Clinton, President George Bush Sr., and Ross Perot. Frank Newport, editor-in-chief of Gallup, says Gallup worked with the Commission on Presidential Debates for the 1992 event, "we recruited, at that point, uncommitted voters from around the Richmond area who came into the debate, and we've been doing it since."

The town hall debate next Tuesday is at Hofstra University and Gallup will again be randomly recruiting uncommitted voters from around the Hofstra area. To recruit, Newport says, "we actually use the same format we use for our standard calling -- we don't tell them why we're calling. We're screening for uncommitted voters, and if they meet that qualification and a few others, we say, 'Congratulations!'"

Newport says Gallup is not involved in selecting which participants get to ask questions or what questions will be asked, "They show up at the debate with nobody knowing what they might ask." That's until moderator Candace Crowley sits down with the group and culls the final questions.