A Mapbox-powered FOSS4G 2017 Map
Live map at https://wboykinm.github.io/foss4g-mapbox/
The FOSS4G 2017 organizing committee has helpfully provided a KML of conference locations. If they make any updates to that file, it can be preprocessed for this map:
wget -c http://2017.foss4g.org/foss4g_locations.kml
ogr2ogr -f GeoJSON foss4g_locations_b.geojson foss4g_locations.kml