Ad spice is a company located right near Duke's East campus, which specializes in printing. I used this company to print t-shirts for a club I was involved in. They're very quick, and have the t-shirts ready within 2 weeks. Also, if you're not sure about the t-shirt design, they will be happy to design it for you. They'll send you a t-shirt proof via e-mail, and if you're not happy with it, you can make whatever changes you would like to. The best thing is, it's very reasonably priced.