powerreviews/moderncomment-Google-Maps-for-Rails
KML - might be still in use on ModernComment - Enables easy display of items (taken from a Rails 3 model) with Google Map, OpenLayers, Bing or Mapquest. Geocoding + Directions included. Provides much options: markers customization, infowindows, auto-adjusted zoom, polylines, polygons, circles etc... See wiki for full description and examples.