Interesting story here in New York Daily News on how some math whizzes at MIT figured out that you could guarantee a healthy return by buying $100,000 worth of tickets in a Massahusetts lottery draw game. They made $8 million by investing only when jackpots hit $2 million or more.
I agree with blogger Eschaton that the article calling this a scam isn't exactly accurate. It was legal to exploit the system by buying sufficient tickets to insure winners. They figured out and beat the system. More of a problem: Lottery officials figured out what was going on and took no steps to step in because, hey, they were still making their profit margin. There are problems if the syndicate got special treatment, such as buying tickets after hours.