The American Civil War Timeline Project
The American Civil War Timeline Project is an interesting attempt to chronologically and geographically map the events of the American Civil War using the open source Simile Timeline. The map includes Wiki style editing so registered users can add geographic/chronological data points to the project.
The site also has two other historical time-line maps:
The World War Two 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.