NPR knocked on doors throughout Colorado to find out how individual voters were responding to Democratic and Republican appeals in the lead up to Election Day. Molly Messick/NPR hide caption

itoggle caption Molly Messick/NPR

Voters cast their ballots during the first day of early voting at the Meadows Mall on Oct. 20 in Las Vegas, Nev. David Becker/Getty Images hide caption

itoggle caption David Becker/Getty Images

Annual "Biketoberfest" participants ride along Beach Street in downtown Daytona Beach, Fla., in 2010. Daytona Beach Visitors Bureau hide caption

itoggle caption Daytona Beach Visitors Bureau

A voter registration form and absentee ballot application at a Franklin County polling place in Columbus, Ohio, on Tuesday. The deadline to register to vote in Ohio is Oct. 9. Matt Sullivan/Reuters/Landov hide caption

itoggle caption Matt Sullivan/Reuters/Landov

Mitt Romney takes the stage at a campaign rally at the Military Aviation Museum in Virginia Beach, Va., on Sept. 8. Brian Snyder/Reuters/Landov hide caption

itoggle caption Brian Snyder/Reuters/Landov