Technical overview
If you are new to Drupal you really should read Drupal general concepts.
Demosphere is implemented as a single Drupal module "demosphere" and a single Drupal theme "demos".
Detailed source-code documentation is available here.
Demosphere module
The demosphere module is quite large and can be divided into several components ("component" here is just a concept, not a specific technical term), all files located in sites/all/modules/demosphere/
source-code documentation is available here.
Event nodes : "demosevent"
The demosphere module defines only one node type. It is called "demosevent". A demosevent describes an event with information like "start_time", place ("address", city ... and many others, defined in demosphere.install).
There currently is no specific node type for places (location + address ...). (Though that could be a nice idea for future work). Several events that happen in the same place have separate copies of the address and other location information (see Demosevent doc). With the suggestion mechanism moderators can easily re-use existing places.
Demos theme
Located in directory sites/all/themes/demos/
css: directory with all the css & css-images - Some information is extracted from inkscape files.
