Go Up To Someone Wearing..
More about Go Up To Someone Wearing..
The same kind of shirt as you and freak out like its the only one ever made besides yours. Ask them questions like where they got it and how they managed to find another one like yours. Just try and make them feel as uncomfortable as possible.
The best way to do this would probably wear a local sports teams t shirt because you could find a lot of people wearing them around your town.