http://finance.yahoo.com/news/Paulson-crisis-happens-once-apf-13635212.html And since he was running GS while the bubble was ballooning, I guess he would know...
The once or twice every hundred years events are called depressions. He is introducing the term slowly. Of course the academic imbecile who studied the Great Depression and has said the Fed has the tools to avoid one is wasting his time with monetary policy to fix an insolvent system.