Possibly the best comic form summary of the CDO MBS scandal. (Sub-prime loans crisis.)

http://www.suburbanhousehunters.com/about/mortgage-crisis/

Of note.

1. SPV's is the general term for the more specific term of SIVs (Structured Investment Vehicles).  Expect to hear more about these in the future.
2. They don't mention that some of the ratings agencies and the financial institutions had shared ownership which could be counted as a conflict of interest.  IMHO If nothing is done legislatively to regulate ratings agencies then this can always happen again. They obviously have a large duty of care.