Use decorators for view_config.  Depend on Kotti >= 0.8b3dev to make patching of Colander unnecessary.  Add some docstrings.
Inherit Calendar from Document instead of Content.  This allows you to have additional formatted (but completely optional) text on your calendar instances.  Make Event implement IDefaultWorkflow.  Add migrations (also the one noted as missing in 0.7a1).
Make files addable to Events and let the editor chose wheter to link to the first contained file of an event from the calendar view (instead of the default linking to the event node).