Welcome to WebmasterWorld Guest from 18.104.22.168
They have been showing up with some regularity in graphic formats 300x250 and 160x600. I have to assume that some poor soul has saved an incomplete template and attached a bid to it, as our overall CPM, CPC, etc., are all normal or slightly above normal.
They look like hell, I must say. They're about as attractive as the old "under construction" graphics everyone was using ten years ago.