Quick update, something's gone wrong. We're not sure what.
It seems to be in the theme (controlling the layout) rather than the database (controlling all the posts and other data).
It looks less like a hack and more like something has been corrupted. What you're seeing here is the default installation that we have rolled back to in order to have something up. We're onto our hosts and we're looking into it. In the meantime, the site is still working normally. It just looks ugly and isn't very user-friendly.