I had an idea that would help promote third parties and help people in non-battleground states make sure their vote would count. This is entirely reliant on the honor system, but I think this could work.
Let’s say Voter A lives in a state that is certain to go to a particular candidate, like Oklahoma or New York. Voter A wants to make sure their vote helps their candidate of choice, so he gets in touch with Voter B in a state that is up for grabs. Voter B is a fan of a third party candidate and would like to help their guy have a decent popular vote, but knows that they have no chance of winning. They have a preference for who wins (i.e. they may be Libertarian but don’t want Obama to win). Voter B pledges to vote for Voter A’s candidate of choice, and Voter A votes for Voter B’s third party candidate.
How does this sound?