Warren Buffett gently knocks Ken Lewis

Warren Buffett is known as one of the most quotable people in the the world of business. His witty asides are a big part of what has made his annual letters to shareholders legendary.

But it's unusual for him to rip into an individual. That's exactly what he did on Tuesday, and he couldn't have picked a better target: Bank of America's (BAC) CEO Ken Lewis.

Speaking at Fortune's Most Powerful Women Summit in San Diego, Buffet referred to Lewis as the "ironic hero" of last September's financial meltdown, whose foolish decision to buy Merrill Lynch at an inflated price saved the global economy -- while also torpedoing his shareholders.