Crucified By Your House
In 1896 William Jennings Bryan brough down the house with his Cross of Gold speech, in which he railed against the gold standard. Americans responded because many felt they had indeed been crucified upon a cross of gold by the bankers and the rich men of the east. Today, it's their houses they've been nailed to, and it's their houses they'll go down with.
As in Bryan's day, today one of the main problems in the US is the monetary system, but unlike in 1896, when tight money was used to keep creditors, most especially farmers, in their place, today it has been loose credit and repeated inflationary asset bubbles driven by uncontrolled money creation which threatens the middle class. While the uncontrolled creation of money isn't limited to the housing bubble, or what is laughably called "sub-prime", since the problems extend far past sub-prime, understanding how real-estate and housing work is integral to understanding the impact, because for most Americans their home is the most important asset they own.
To talk about Housing one has to first talk about what money is. In the modern world money is generally created as debt. The simplest form is where someone goes to the bank, say "I have asset X that's worth Y and I want to borrow money." The bank takes a look at the asset, checks you out and if they think you can pay them back, they give you the loan. Because a bank can loan multiples of the money it has been given to keep for other people (deposits) most of that money is, in effect, created out thin air.
That's the fractional reserve system, and it creates money.