Chain Mail: a group-driven story written through mail

From the publisher: "In Chain Mail, you and your group are joining forces to create the best genre story possible. Remember those wonderful story-telling experiences where you go around the circle contributing a few sentences to an ever-growing, changing, and evolving story? That’s Chain Mail. But it's happening the old fashioned way: via old fashioned, on paper, stamped and everything mail. However, there are a few things to help guide you on the path."