From ESRI:
"Inspire the world with GIS
Participate in the international celebration of GIS technology. GIS is a scientific framework for gathering, analyzing, and visualizing geographic data to help us make better decisions. On GIS Day, help others learn about geography and the real-world applications of GIS that are making a difference in our society. It's a chance for you to share your accomplishments and inspire others to discover and use GIS. Even though celebrating may look a little different this year, sharing GIS is more important than ever."
GIS Day Website