This excerpt taken from the ATVI 10-Q filed Feb 8, 2006.
Content Rating. For those Sales Territories that utilize a content rating system, Microsoft will not acceptsubmission of a Software Title for Certification approval unless and until Publisher has obtained, at Publishers sole cost, arating not higher than Mature (17+) or its equivalent from the appropriate rating bodies and/or any and all otherindependent content rating authority/authorities for the applicable Sales Territory(ies) reasonably designated by Microsoft(such as ESRB, ELSPA, CERO, etc.). Publisher shall include the applicable rating(s) prominently on FPUs and Marketing Materials, in accordance with the applicable rating body guidelines, and shall include the applicable rating in a header file of the Software Title and in Online Content, as described in the Xbox 360 Publisher Guide. For those Sales Territories that do not utilize a content rating system, Microsoft will not approve any Software Title or Online Content that, in its opinion,contains excessive sexual content or violence, inappropriate language or other elements deemed unsuitable for the Xbox 360platform. If, after Commercial Release, a Software Title is determined as suitable for adults only or otherwise as indecent, obscene or otherwise prohibited by law, the Publisher shall at its own costs recall all FPUs. Publisher hereby represents and warrants that any Online Game Features and other game-related Online Content not included in the initial Software Title FPU will not be inconsistent with the content rating (or, in those countries that do not utilize a content rating system, with the overall nature of the content) of the underlying Software Title. Content rating information and requirements may be further described in the Xbox 360 Publisher Guide.