Via ColorLines, The Root links to an Ohio news story about 10-year-old Nikko Burton who, as one of only two black students in his classroom, was asked to participate in a mock slave auction. White students in the class would have poked and prodded Nikko, just as might have happened at a real slave auction, and when Nikko refused to participate, he was disciplined, according to reports. Also according to reports, the school district has apologized to Nikko's family, but the teacher hasn't apologized to Nikko.
This is one of those cases in which I'm sure the intention was good. As Jamelle wrote below, this isn't a poor idea in theory. The teacher was groping, and I mean that sorta literally, for ways to demonstrate the abhorrence of slavery to the class. But it's the racism of ignorance that doesn't clue her into the racism that still exists today, the racism Nikko has likely experienced already, and the racism of requiring him to be fodder for a history lesson because he fit the part. Meaning well doesn't diminish Nikko's humiliation, and it doesn't undo the more subtle lesson about relative power and stereotypes that other kids in the class likely picked up.