One of my favorite non-biblioblogs, Marginal Revolution, has an occasional feature called "Opposite Day". On Opposite Day, the primary bloggers Tyler and Alex don their alter egos "Tyrone" and "Axel" and play devil's advocate, arguing opposite what they normally would.
Several bibliobloggers liked the idea, so Brannan proposed a set of guidelines:
Introduce your question/topic. It can be anything, really, as long as you're arguing opposite what you normally would. Arguing against known positions is always enlightening (for reader and writer) but don't feel bound to that.
Introduce your alter ego. I think this is important, we'll need to make sure that no future google searches stumble upon these entries leading folks to think you yourself are actually supporting something completely opposite of what you normally would. I think Tyler Cowen's example of always introducing "my good friend Tyrone" as the author, then blockquoting as if he's copied the text in from an email, is a good model.
Make your (alter ego's) point. You can be short or long, doesn't matter. You might be surprised how well your alter ego can argue.
And he suggested July 10th as the Opposite Day for those who blog on topics in Biblical studies. Here is the result, and it's as interesting as one would think.