GIS Day is November 14th, 2007. According to http://www.gisday.com, "on any given day, more than two million people around the world use GIS to improve the way their organizations see [users]. GIS Day provides an international forum for users of geographic information systems (GIS) technology to demonstrate real-world applications that are making a difference in our society."
GIS Day is November 14th, 2007
November 1, 2007