This one's not as much of a shirt as it is a totally awesome uniform to fight crime and traverse near light speed while fighting crime. It's still cool though and Sheldon wore it so... yeah. I'd recommend taking Raj's advice and purchasing at least 4 of these — one for you and one for at least three of your friends. Then proceed to walk behind each other all night so you'll look like one person moving incredibly fast. The illusion should be incredible. INCREDIBLE.
Featured on The Big Bang Theory episodes
S01 E06: "The Middle-Earth Paradigm"
S02 E18: "The Work Song Nanocluster"
S04 E11: "The Justice League Recombination"