Where/When did the economy of the United States go sour?

In lue of the economic status of the United States today, I thought would be an interesting topic of dicussion to attempt to pinpoint where and when the ecomony took its nose dive. You turn on the news and you hear alot of people talking about HOW the economy is going sour, but not alot of discussion on WHY WHERE WHEN it's doing so. There really isn't a wrong answer to this question, it's a matter of opinion!