Borror0 provides an analogy for the Greece crisis on reddit

This link has a fuller treatment: 

Imagine if your mortgage's interest rate was raised from 5% to 19% overnight. All of a sudden, your minimum payments rose by a lot and you can no longer afford what you could afford before. Imagine if, on top of it, your boss reduced your hours at work because of the bad economy and thus your revenues went down while your mortgage's interest rates went up. That's Greece problem, in a nutshell.