Patrick King had already designed some shirts featuring type, but it was a children’s shirt with Helvetica in it’s name that spurred the start of the popular TypographyShop. He originally ran a politically themed t-shirt line, but noticed that the term “Helvetica T-shirt” was bringing in the most traffic. However these searchers were seeking a shirt honoring Helvetica itself, not just words set in the font. So they did a poll, then test launched on the political site with King’s Helvetica Neue Descending shirt. It was a hit! Helvetica Neue Descending went viral, spreading across social networks and being featured on scores of blogs (now mine included). Sales went off the charts and TypographyShop was born. Since 2008 they’ve been giving the people what they want.
I’m a fan of their ilovetypography/love series. Note that TypographyShop shirts really only come in black or white, which is fine with me considering most of my tops are black. They also have hoodies (pullover/zip-up) and mugs. There are plans in the future to expand to posters and magnets, even pillows. Also, a part of sale proceeds is donated to The AIGA Education Fund which is used to help students nurture their design talents.