Paul M. Jones has started an interesting discussion rethinking the MVC pattern as applied to the web, which he has dubbed Action-Domain-Responder (ADR). If you haven't given it a read yet, click the link and do that; this page will still be sitting here waiting when you return.
I agree with a ton of it — heck, I've contributed to it a fair bit via conversations with Paul. But there's been one thing nagging at me for a bit now, and I was finally able to put it into words recently.
Controllers — Actions in ADR — can be explained as facades.