We built an interactive map to mark locations based on category. The map needed to toggle sets of locations on and off through checkbox controls. I knew how to mark a single location, but was a little unsure about adding, tracking and removing multiple markers. As well, the functionality needed to scale as the bureau added partners.
Luckily, Google provided a link to the open source MarkerManager, since their GMarkerManager is deprecated. The tool is part of the GMaps Utility Library project, which provides quite a few nice extensions to Google's functionality. As you'd imagine, the MarkerManager class allows for management of hundreds of map markers.
While this is not the most exciting topic, I'd suggest bookmarking the library for when you need to do a little bit more with a Google Map than the built-in API offers. There's even an AS3 library for Flash developers.