World War Two Timeline Project
The World War Two Timeline Project is an interesting attempt to chronologically and geographically map the events of World War Two using the open source Simile Timeline. The site has recently added Wiki style editing to the map. Registered users can now add geographic/chronological data points to the project.
The site now also has two other historical time-line maps:
The American Civil War Timeline Project
The Napoleonic Wars Timeline Project
With all three maps, historical events are added to the map when you use the time-line interface above the map.