In my Sports Economics class, the last topic I go over is the Price & Wolfers paper on racial bias by NBA referees. The authors looked at the 1999 - 2002 NBA seasons and controlling for everything that anyone could think of as to why this would not be true, find that it is true. This is an astounding result - which is why I save the best for last in Sports Economics.
Subsequently, the authors have looked at the 2003-2006 time period and find the same result, but then once the "cat was out of the bag" meaning once that this result was made public, the racial bias effect has disappeared using 2007-2010. This is found in the recent issue of Business Week (h/t Will).