A few years ago, I had a run-in with somone who was pushing a pyramid scheme by the name of "Pre-Paid Legal." I was fascinated by the way in which the pitch was set up to try to shut off critical thought in the recipient. I was even more fascinated by the way in which the recruitment events resembled religious gatherings.
I wrote an article about this for the (now defunct) Skepchick magazine. I was recently reminded of this when a representative of another pyramid scheme - the Mona Via "superjuice" fad - approached me recently.
Here's the article