Answer: Civilization

In the summer of 2010, an official proclamation was issued by the Governor’s Office of Maryland: September 21st shall henceforth be known as Civilization Day in honor of the enormously popular simulation game Civilization (and timed, conveniently, with that year’s release of Civilization V).

Meier and his game studio Firaxis are based out of Maryland, and the honorary day was awarded both for Meier’s contributions to the video game industry as well as the efforts of his company to support and foster creativity in young adults.