It almost always surprises me every year, when I get an email from ESRI saying that today is GIS day, apparently ESRI chose it. Not specifically the 19th of November, but the third Wednesday in November. I assume this is because like myself Wednesday can be a bit of a slog. Here is the internets description of GIS day:

GIS Day is an annual event celebrating geographic information systems based technologies on the third Wednesday of November. The event first took place in 1999. It was initiated by spatial analytics software provider Esri. Esri president and co-founder Jack Dangermond credits Ralph Nader with being the person who inspired the creation of GIS Day. He considered the event a good initiative for people to learn about geography and the many uses of GIS. He wanted GIS Day to be a grassroots effort and open to everyone to participate. Today, the event provides an international forum for users of GIS technology from across the GIS industry to demonstrate real-world applications that are making a difference in society.

Of course as an avid Open Source Software user I promote QGIS over ArcGIS everyday of the week especially since ESRI changed their subscription model. So “Happy GIS Day” go forth and create great maps!