I got to talking about this story with someone yesterday. It's one of my favorites. Francis finds himself having a temptation against chastity, so he goes out into the snow and makes himself a snow wife.
Seeing that he has a wife, Francis says, "Well, Francis, now that you have a wife you will certainly have some children!" So he makes two snow sons and two snow daughters.
Now that he has a whole household, Francis completes his new family by making two snow servants to help around the house. Then Francis becomes alarmed when he sees he has seven people to care for. "Can't you see your family is freezing to death," he says to himself, "you had better go get some work so as to buy them proper clothes!" And it gets worse when he realizes that they are probably hungry and he has to go find them something to eat.
By giving himself all this anxiety, Francis cures himself of his temptation. What I find brilliant about the story is that by doing something ridiculous, Francis corrects his thinking and makes it more realistic. And this is part of the anatomy of temptation: we are attracted to something without seeing the whole picture. We sin because our thinking is distorted and we look for happiness within an incomplete conception of things.
Francis corrected his thinking, using the snowmen to shock himself into a more realistic view of what a non-celibate life would mean for him. This, then, is part of the cure for temptation and sin: correcting our thinking, bending it to reality. For Francis this meant making five people out of snow; nowadays this is called cognitive therapy.
My favorite version of this story is in St. Bonaventure's Legenda maior of St. Francis. When I first began to learn Latin I was excited to look up this story and see what the Latin word for "snowman" might be. Unfortunately it seems that snowman technology was not very advanced in the thirteenth century, for all Bonaventure says is that Francis made some "lumps" or "masses" out of the snow:
Insuper et mirando fervore spiritus animatus, aperta cella, foras exivit in hortum, et in magnam demergens nivem corpusculurn iam nudatum, septem ex ea plenis manibus coepit compingere massas. (Bonaventure, Legenda maior, chapter 5)
I don't know of an english translation of the Legenda maior that can be had for free. There is however, a nice trade paperback, and a recent translation in the latest series of Franciscan documents.