In one episode they all attend a Halloween party. Sheldon is a super smart, yet bad in public social situations geek. His costume was The Doppler Effect. A series of white stripes on a black shirt and the impression of them getting wider and thus louder. No one at the party seems to get it and thinks he is a zebra. His persistance in the validity of his costume made it special because as a movie/convention going geek, I have worn many a costume that maybe only I got. But it didn't matter, the costumes were still appreciated by the fans around me.
Here is Sheldon and his Doppler Effect costume from the show.
My version is just a shirt (I couldn't copy the pants) and not quite so many stripes, but I am very proud of it. I didn't do much more then think of it and get Thomas to help me. I baked him cookies while he put stripes on the shirt. It came out great. I will be interested to see if any recognizes me tomorrow....of if they all think I am a zebra.