List of AO-rated products:
http://en.wikipedia.org/wiki/List_of_AO-rated_products
Before this, the only console title to receive an AO rating was San Andreas. This game initially received an M rating, but was re-rated AO after the "hot coffee" mod was discovered. If the AO rating sticks, Manhunt 2 will be the first console title to be released with an AO rating.