Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

How to invest for the event of a US default? 
If the US economy crashes at all suddenly, the global economy goes with it. In that case, yes, the postapocalyptic scenarios may be the best answer. But that's got so low a probability of happening that you'd be a fool to invest in it. If you really feel the need, consider investing in the companies which supply those activities. The big winners in the California gold rush were the general stores that sold supplies to the speculators.