I love maps. And I love google for making maps useful, interactive, and cool. When they released the API I wanted to use google maps as a filter. That is, I wanted to filter location-based data based on what is viewable on the map canvas. Google currently does this if you goto maps and do a search. For example, search for bars and markers appear for all bars that exist on the map canvas your viewing. The difference between that and this project is that with this project you control the data source, not google.
My first working example is GCM - Google Calendar Map. It uses a google calendar as the data source, plotting all calendar events with a valid location on a map. This way you can control the data source by populating the calendar with whatever data you want. For more info, check out the GCM Project page or view GCM prototype in action.
The example code is messy. I wanted to get something up and running so i can experiment with features. My methods often involved pasting code from other sources, so forgive me for the quality of the code. I only recently pulled out some of the core javascript, cleaned it up, and put it in the src directory. It still could use some work, and i welcome suggestions.