For those of you who teach about the Great Depression, there's always the contention that Roosevelt's New Deal and the spending for WW II was an example of Keynesian economic policy. This piece by economic historian Price Fishback that appeared on the Freakonomics site (HT to Don Boudreaux for the pointer) makes a compelling argument that the New Deal and WW II, despite whatever else they may have been, were not an example of Keynesian policy - the deficits in the Depression were too small. (And that criticism came from no less than John Maynard Keynes.) And it seems WW II was a special case. Anyway, the post makes an interesting read.
I look forward to your thoughts.