The sub-prime mortgage infection has already spread to affect most areas of the U.S. economy and the world. What started as one of the after-effects of the "Great Greenspan Depression of the Millennium", it has recently threatened to destabilize the very financial system of the most powerful economy in the world. This presentation called "A primer on Sub-Prime Mortgages" is entertaining while at the same time very educational. It describes in simple terms some of the reasons that got us into this mess.