Here are a selection of JG posts on the Atonement. Feel free to add more in the comments, or links to elsewhere. Also feel free to discuss any of the posts for which comments are now closed.

The Strange Doctrine of the Double Atonement (in other words, why both Gethsemane and the Cross?)

Unexpected Lessons in Theology from Dead Economists

the Royal Largesse Theory of the Atonement

The Meaningful Choice Theory of the Atonement