I always just wanted the ycombinator on a shirt, and spreadshirt looked easy enough to use so I gave it a shot. Here's what turned out: http://wright.spreadshirt.com/men-s-heavyweight-t-shirt-A757...

I'd highly recommend spreadshirt by the way. The site was incredibly easy to use to create the shirt and storefront, and if the shirt quality is anything like the American Apparel shirts I own, it should be very good quality shirts as well.