The Black Iron Prison is a metaphor developed by the PrincipiaDiscordia.com spags. It is discussed and dissected in this pamphlet: http://www.cwyohba.org/noexit/cramulus/Black_Iron_Prison_July2007_full_page.pdf
browse the web version at http://www.principiadiscordia.com/bip/1.php
The basic math is that the more frequently people develop their critical thinking skills, the better it is for everybody involved.
The booklet attempts to give people the impetus and motion to "Think for yourself, shmuck!"
Originally intended as an attempt to revisit the parts of Discordia most relevant for a modern audience, the Black Iron Prison grew into its own work. It remains the Principia Discordia's dark cousin.
Check out the Black Iron Prison project wiki at http://www.blackironprison.com/