In the United States, if a video game has a range of content, it receives the most restrictive rating that applies. In other words, if a game is mostly child-friendly but has a few scenes of intense graphic violence, it's rated based on those violent scenes, not the average of the whole game. Below are the ratings:

• Early Childhood: Games in this category should be fine for children as young as three years old. These games have no violence, sexual content, or even situations where onscreen characters are in danger. You probably can't find any Xbox 360 games rated EC.
• Everyone: The Everyone (E) category is misleading. It actually means everyone over six years of age. A lot of Xbox 360 games fall into this group, including popular titles such as Project Gotham Racing, RalliSport Challenge, the Harry Potter games, LEGO Star Wars, and most sports games, such as NFL Fever, NHL 06, and NBA Street. Even Barbie's Wild Horse Adventure is rated E rather than EC. (When Barbie navigates a cliff, those instances push an otherwise completely safe game into the E category.)
• Everyone 10+: These games are suitable for kids ten years old or older. This rating doesn't get used very often. Games in this category generally contain the same elements as games rated E, just with a bit more than "minimal" content. In addition, more revealing outfits or mild bits of innuendo might show up.
• Teen: Teen (T) games are aimed at 13-year-olds and older. Teen-rated games increase the violence and may include blood, strong language, or mildly suggestive themes. This category contains many titles, including the new Tony Hawk game American Wasteland, Kameo, and Need for Speed.
• Mature: Mature (M) is aimed at "kids" age 17 and older. Games in this category can contain (among other things) intense violence, strong language, and some sexual content. Perfect Dark Zero, Halo, and Quake 4 all fit in this group, as does the infamous Grand Theft Auto. The first three games fall into this category mostly for their violent content, but Grand Theft Auto hits on every possible style of inappropriate content, including drug references, sexual references, and strong language, along with the standard intense violence.
• Adults Only: The most restricted rating in the system, Adults Only (AO), is reserved for games best left to folks who are 18 and over. The only popular Xbox game to receive this rating is Grand Theft Auto: San Andreas.

Expect to see a rating on any content that you purchase or rent, and be wary of any content that doesn't have a rating. Unrated games and movies may have shocking violence, language, or sex.