Hi, I think this is mainly a UK opportunity, however not certain. This is using the profit accumulator website doing something called matched betting.
It involves utilising the free bets what bookies provide when you join. Take a look at the intro video and see what you think. One thing i can say is this is a very legit thing to do and is certainly nothing to do with a ponzi scheme.
Its been discussed in a few of the UK newspapers in the past, and those in the UK will probably have heard of martin lewis, a money saving expert. Well its on his forum 'money saving expert'.
Anyway i was asked to post it so here it is.

Introduction to Matched Betting - Profit Accumulator