Wanna be a Keynesian?

Paul Krugman explains this depression: 

Let’s start with what may be the most crucial thing to understand: the economy is not like an individual family.
 Families earn what they can, and spend as much as they think prudent; spending and earning opportunities are two different things. In the economy as a whole, however, income and spending are interdependent: my spending is your income, and your spending is my income. If both of us slash spending at the same time, both of our incomes will fall too.
And that’s what happened after the financial crisis of 2008. Many people suddenly cut spending, either because they chose to or because their creditors forced them to; meanwhile, not many people were able or willing to spend more. The result was a plunge in incomes that also caused a plunge in employment, creating the depression that persists to this day. 

The solution— 

So what could we do to reduce unemployment? The answer is, this is a time for above-normal government spending, to sustain the economy until the private sector is willing to spend again. The crucial point is that under current conditions, the government is not, repeat not, in competition with the private sector. Government spending doesn’t divert resources away from private uses; it puts unemployed resources to work. Government borrowing doesn’t crowd out private investment; it mobilizes funds that would otherwise go unused.

Bonus: Loudon Wainwright III sings the "Paul Krugman Blues."