Haha! T-shirts! One of my favorites is actually one that I made (I'll see if I can find a pic or something.) It uses the iron on type of thing. For those, you need to print out what you want it to say backwards so that it will show up forwards when you iron it on. I decided to take advantage of this: I didn't flip it, I uses a weird text and made it read "dyslexic." So, I'd get a lot of odd looks because people wouldn't realize that it's backwards. Cute, not amazing, but cute.
I love how it takes everyone I know a different length of time to figure out what it says: some get it right away, some don't know what dyslexia is, some people it takes a couple of years before it hits them (w/o me explaining it to them.)