I saw this last week and exchanged emails with Bob about it. It is a very creative way to challenge Krugman to debate the fundamentals of business cycle theory and the evidence on the effectiveness of government policy.
As readers of this blog know, I am myopically academic in my own approach, but careful readers will also know that I respect broader outreach efforts to spread the ideas of free enterprise and classical liberalism. I just have no real comparative advantage in these activities myself, and I don't think these sort of activities have positive spill-over effects for those of us focused on the academy. But that is a positive statement, not a normative position. Let me be clear, I think these efforts are a net plus for the public understanding of economic freedom. I found the Russ Roberts' effort in the Fear the Boom and the Bust to be awesome, I think the PBS video clip on Tullock and voting is fantastic and use it in my classes. And I have to say that Bob's creative way to attempt to get Krugman to debate him on the merits of Austrian Business Cycle theory is amazing, so amazing in fact that I am in awe of his audaciousness in proposing it. Congratulations Bob, hope you get your wish.