Every year, SIGTE organizes workshops and a conference about Free GIS software in Girona.
This year I gave a workshop about D3js mapping.
The slides (in Spanish) are here: http://rveciana.github.io/Mapas-web-interactivos-con-D3js/
The examples can be found at my bl.ocks.org space: http://bl.ocks.org/rveciana named with the prefix JSL 2015.