Shaftlands Survival world
Minecraft is a computer game in which players can build 3D worlds. Tectonicus is a minecraft map renderer that can help you create map tiles of Minecraft 3D worlds for Google Maps.
Maps made with Tectonicus created map tiles can include all the normal features of Google Maps, including map markers and information windows. Because Minecraft contains a first person view it would even be possible to create custom Street Views for a Minecraft Google Map, although disappointingly no-one has done this yet.
The Minecraft Wiki has links to a number of Minecraft Google Maps, if you are interested in seeing what players have created.