In Minnesota there is not supposed to be early voting except in certain cases, like travel, medical, but you can change your vote on election day, or vote for Obama twice? I smell fraud...
http://minnesota.publicradio.org/display/web/2008/09/25/absentee_voting/
Unlike early voting in Iowa, Minnesota voters can change your mind if you’ve voted absentee. You just have to show up at your polling place on Election Day and cast a new ballot.