They're these round graham crackers with marshmallow in the middle and dipped in chocolate, about as big around a DVD. I actually ate so many of them when I was a little girl that I can no longer stand the taste of them. We drink them with RC Cola (a localish brand), and there's an RC Cola and Moon Pie festival every year in this little podunk town near where I live. I've never been, but I keep meaning to. More here.