"How to Hack a Diebold Voting Machine"
Take a look at Marty Kaplan: How to Hack a Diebold Voting Machine on The Huffington Post.
I suppose it might help to know the file format of the information you need to put on the flash drive and the number of people who signed in at the polling place (minus the number who have voted at the other machines). Oh, and don't take too long doing all this, lest the election officials become suspicious.
Memo to self: submit this to "The Mythbusters" to see how long it takes to get it done.