From time to time, I have a go at tinkering with various maps mashups, that may or may not be OUseful.
Here are some of them...
The gCalMap generator provides a way of displaying Google Calendar events on a Google Map. Simply provide a Google Calendar ID and get the embed code for a map (or side by side calendar and map) displaying the events.
TRY IT OUT HERE: gCalMap mashup utility.
Originally described at: Displaying Google Calendar Events on a Map, with follow up posts: "calmap" on OUseful.info
Write a blog directly from Google MyMaps. This utility will then generate a URL that points to a geoRSS feed for your MyMap geoblog.
Originally described here: MyMaps GeoBlogger - Blogging From Google Maps