Reference to the cult classic movie "Napoleon Dynamite". Pedro, a quiet Mexican immigrant kid, is running for high school student body president. As part of his campaign, he distributes T-shits with "Vote for Pedro" printed accross the front.
An article of clothing (usually a t-shirt) that is yet another trail-off piece of merchandise the creators and affiliates of Napoleon Dynamite are using to suck the largest amount of money possible out of what's left of their film.
Look at Rachelle. She bought a 'vote for pedro' shirt on our Ottawatrip. Bitch.