has changed the rating of the PC version of Oblivion from T (Teen) to M (Mature). The ratings board enacted
the change because the game contains stronger depictions of violence than what were featured in the content that was
submitted to determine the original rating. But more importantly, the new M-rating is a result of hidden (archived)
topless skin files that can be accessed via a fan-created mod.
At this time, it's unclear if a recall will be issued, but the new rating, along with the addition of a "nudity" warning, will be applied to copies of Oblivion that are still on store shelves. It's also possible that Take-Two will force Bethesda to remove the archived files and re-release the game, in turn, regaining the T-rating.
Update: the Xbox 360 version has also been re-rated to M due to "Blood and Gore, Language, Sexual Themes, Use of Alcohol, Violence" [via ESRB]. [Thanks, Scott]