I have 3 of them.
One is a light purple one that supports the C.A.R.E organization that J.K Rowling teamed up with to aid reading in developing countries. I normally only wear that one to school or when I'm tutoring kids in reading, heh
Oh, it is imprinted with, "Reading is Magic"
My second one is for support of adopting children, I can't remember though the specific organization however. It's a bright magenta color.
And my third one is the Social Work band, it's a dark teal color. I bought one from my sister's work (she's a social worker, heh) and normally wear that one and the 2nd one when I'm volunteering there.