You'll be hearing more about this, so hears a definition:
The PJ Tatler » Obama’s Beloved Professor Derrick Bell
Critical Race Theory, in a nutshell, argues that the law is a weapon of the majority whites to oppress “people of color.” It argues for “structural racism”–the idea that American institutions are aligned against blacks, whether the oppressor is the criminal justice system, a cabdriver without a fare, businesses, government, Domino’s Pizza, banks, or the police.
Critical Race Theory does not view the law as applying equally to all Americans, but advocates for racially unfair implementation of the law to right past injustice.
Most of the crackpot racial grievance you hear today has a philosophical foundation in Critical Race Theory. It is a counter-American, collectivist idea. Reparations, race-based hiring and excusing New Black Panther voter intimidation are some of the evil fruits of Critical Race Theory.