We've had a lot of comments on the shirts we made for the Atticus Disneyland Birthday Bash. We made them online at Disney. Just go into the shopping area and there will be a link for creating your own stuff; shirts, mugs, stamps, whatever. There are hundreds of images available.
Tricia, Atticus and I picked a character for everyone and placed them on the front of the shirt. On the back they all said "Atticus" across the top like a sports jersey with the number "3" centered below.
They garnered much attention, and as one parent told us, "you just earned a bunch of parent points." I hope so, they weren't cheap!