There was a riot yesterday afternoon in the CCA-run North Folk Correctional Center in Sayre, Oklahoma. Though no staff were injured and no hostages taken, at least 20 prisoners were injured in the disturbance, including one who was stabbed. Of course, the prison couldn't handle the riot itself, and 6 units from the state police had to assist (how's that for privatized public services?)
Here's a bit more on the situation.
UPDATE: At least 46 prisoners were injured in the riot, with at least 16 having to be transported to a hospital to treat their injuries.