Well the good news is that the good folks at Google/Blogger tech support have figured out what's wrong. The bad newses are 1) yes, my account was hacked and 2) no one's quite sure how to fix it yet.
The part I can't figure out is why anyone would hack my account and then just mess with layout. I'd think they would have replaced all my content with REPUBLICANS RULE DEMOCRATS DROOL or something. (Bonus points for all who get the reference. Only parents will.)
In the meantime, Craig Robinson has a must-read insider perspective up on the Dix vs. McKinley civil war.