basically it is a lottery where you cant lose any money. you would buy a "ticket" thats maybe $50, and that money, along with other players is invested and the profits of those investments goes to the winner. you automatically get you buy in money back.
full details: http://freakonomicsradio.com/who-could-say-no-to-a-no-lose-lottery.html
and a site that does it: http://www.savetowin.org/
