Event Calendar started as a replacement for an antiquated script to generate meeting invites with attached ical. It has since grown to be a full fledged event calendar system for public events. Important to Event Calendar is the theory of multiple interfaces, where any data in the system should be accessible in a multitude of ways. For events, this means via nice HTML, iCal, XML, and JSON. Event Calendar also includes integration with Google Maps for directions to event locations.
Refinery is a Ruby on Rails content management system for small business sites where the client needs to be able to update their Web site themselves without being bombarded with anything too complicated. It is truly aimed at the end user, making it easy for them to pick up and make changes themselves.
render_inheritable is a Rails 3 plugin that allows one to inherit or override single templates for controller hierarchies. With this gem, a template is searched in the current controller's view folder (as usual). If it is not found there, the template with the same name in the view folder of the superclass controller is used. Finally, views and partials remain DRY.