November 19th is the date for GIS Day 2008.
This posting on Geography Matters announces that GIS Day focused web sites can be submitted to be included on this collection of GIS Day web sites for the public to access. If you would like some help in creating your GIS Day webs site, take a look at these templates to get you started (download .zip file here)! Get lots of information on GIS Day materials as well.
There is a lot of useful information about setting up and planning for a GIS Day event on the GIS Day web site at http://www.gisday.com.
Hope you have a fun and successful GIS Day event!