I don't know about the when but I have a pretty good idea about what the "something" will be.
Eventually this government will no longer be able to fund itself and service its debt. This is a mathematical certainty. We're looking at sovereign default and the utter destruction of our currency.
It's going to be unimaginably ugly.
http://finance.yahoo.com/q/bc?s=VUSTX&t=3m&l=on&z=m&q=l&c=
That is a reasonable conclusion. But what is baffling is why anyone would today loan the U.S. money for 30 years at 3.85%? What foolish overseas dolts would buy these things? ( 30-year treasuries ..)