This post is part of our feature on Money Winners of 2008. See all 20.

Lots of people thought real estate was overpriced. Many worried that banks were giving out mortgages too cheap. But what did you do about it? (Either to help the situation or to make money.) Jeff Greene, a real estate mogul in California, actually found a way to bet against the subprime mortgage folly. He made $450 million -- at least that was the count earlier this year.

Well, he didn't just think of it on his own. He basically took the idea that his friend, hedge fund manager John Paulson, had. Paulson thought that, as an individual, Greene wouldn't be able to do this complex a transaction. According to the Wall Street Journal he even used special software so investors in a hedge fund Paulson created just to exploit the subprime crisis couldn't pass on his strategy.

How Greene and Paulson made money involves two financial terms you've probably had to learn this year and never want to hear again. Collateralized debt obligations (CDOs) are the way mortgages are packaged and sold to investors in various slices of risk. Credit default swaps are the holders of those investments insured themselves -- by buying what was like unregulated insurance from one another. The credit default swaps are what got so many big companies in trouble -- they had to pay up on investments that went bad. So Paulson shorted CDOs and bought some credit default swaps.