Hello everyone,
There are two meta-sites that I often recommend. Geolode is a catalog of websites that provide free GIS data, maintained by the GIS librarian at Cornell University as a personal project: http://geolode.org/
The OpenGeoportal (together with the GeoBlacklight Community) is a growing consortium of universities that provide access to their GIS data through common search portals: http://data.opengeoportal.org/
There’s also the old-fashioned approach: keeping track of a handful of good sites. I haven’t checked the list I keep here in awhile (so there may be a few broken links) but it’s a good start: https://www.baruch.cuny.edu/confluence/display/geoportal/External+Links+to+GIS+Data
This page is on our Geoportal at Baruch that I maintain; if you don’t mind a little shameless self-promotion 🙂 we have some useful data there: https://www.baruch.cuny.edu/confluence/display/geoportal/
Good luck with the workshop (I’d stop by but unfortunately I’m not free on Weds evenings).
Best – Frank
Frank Donnelly | Geospatial Data Librarian | Baruch CUNY