Irregularities in Wisconsin
"A task force looking into potential voter fraud on Election Day said Tuesday that it found more than 200 felons voted illegally and more than 100 instances of people voting twice or using fake names and addresses.
"The investigators found hundreds of fraudulent votes in all and counted 4,600 more ballots than registered voters in Milwaukee — but did not uncover any proof of a plot to alter the outcome of the hotly contested presidential race in Wisconsin's largest city. They also found ballots cast using the names of dead people."
I've felt like this might be happening ever since 2000 when I heard students discussing rumors about people who had cast an absentee ballot in their hometown and then registered to vote on Election Day in Madison. This wasn't a conspiracy, either - someone made the comment that they didn't realize it was illegal, since they lived in both places. It's completely unsubstantiated, but the sort of thing that could easily happen, and probably will given a large enough population sample.