Grist: Normally when we hear about Charles and David Koch making it rain from their multi-billion dollar empire, its to adorn Tea Party candidates during campaigns or to fund free-market advocacy organizations like Americans for Prosperity. But earlier this month, the Koch Bros., as theyre affectionately called, dropped $25 million on the United Negro College Fund (UNCF), to aid scholarships for black students and to help historically black universities. It was the fifth largest donation UNCF has received...