Rating system
Rating systems are government or industry created methods of determining the appropriateness of content in games, films, and on television based on age.

Games 
Entertainment Software Rating Board (ESRB) - United States, Canada, and Mexico (1994-current)
Videogame Rating Council - United States (1993-1994) - replaced by ESRB
Recreational Software Advisory Council (RSAC) - United States (1994-1999) - replaced by ESRB
Australian Classification Board - Australia (2006-current)
Office of Film and Literature Classification - Australia (1995-2006) - replaced by the CB
Pan European Game Information (PEGI) - Europe (2003-current)
British Board of Film Classification (BBFC) - United Kingdom (-2012) - replaced by PEGI
Entertainment and Leisure Software Publishers Association (ELSPA, formerly European Leisure Software Publishers Association) - United Kingdom (1994-2003) - replaced by PEGI
Syndicat des éditeurs de logiciels de loisirs (SELL) - France (1999-2003) - replaced by PEGI
Asociación Española de Distribuidores y Editores de Software de Entretenimiento (aDeSe) - Spain (1996-2003) - replaced by PEGI
Unterhaltungssoftware Selbstkontrolle (USK) - Germany
Game Software Rating Regulations - Taiwan
Media Development Authority (MDA) - Singapore
Departamento de Justiça, Classificação, Títulos e Qualificação - Brazil

Theatrical and home video 
Motion Picture Association (MPA), previously Motion Picture Association of America (MPAA) - United States
Canadian Home Video Rating System - Canada (except Quebec)
Régie du cinéma du Québec - Canada (Quebec)
Office of Film and Literature Classification (OFLC) - Australia
British Board of Film Classification (BBFC) - United Kingdom
Irish Film Classification Office (IFCO) - Ireland
Central Board of Film Certification - India
Freiwillige Selbstkontrolle der Filmwirtschaft (FSK) - Germany
Netherlands Institute for the Classification of Audiovisual Media - Netherlands and Belgium
Media Council for Children and Young People - Denmark
映画倫理管理委員会 (EIRIN) - Japan
香港電影分級制度 (HK) - Hong Kong
Media Development Authority - Singapore
Departamento de Justiça, Classificação, Títulos e Qualificação - Brazil

Television  
TV Parental Guidelines - United States
Canadian TV Classification System - Canada