UPDATE 20th December 2012: Version 2.0.0 has been released! This version adds support for different map providers using the Mapstraction library, fixes issues with HTML entities such as & and " and adds support for widgets!
Every Calendar +1 is a WordPress plugin that provides custom post types for Calendars and Events. There is an annotated document with a description of how everything works published here. Source code is hosted on GitHub. If you like this plugin consider making a donation to one of the causes I’m supporting.
Calendars can contain an unlimited number of local events and can syndicate content from an unlimited number of external calendar providers as long as the syndicated feed is supported by Full Calendar.
Events support a location and geocoded lat/lng coordinates for more precise marking.
The maps interface is pluggable so you can use any maps provider you like (and they don’t have to support geocoding but it’s better if they do).
Any issues feel free to leave a comment below.