Group Calendar provides an in-game calendar for planning, signing up, and managing events. It can be configured for single-guild use or for multi-guild alliances.
The user's manual can be found at http://wobbleworks.com/groupcalendar/manual/
Recent Changes
v4.5.1 Changes
* FEATURE: Added Isle of Conquest battleground
* FEATURE: Added Trial of the Champion dungeon
* FEATURE: Added Trial of the Crusader and Trial of the Grand Crusader raids
* BUGFIX: Corrected Maybe checkbox to send Maybe instead of Standby to the organizer
v4.5 Changes
* FEATURE: Added Ulduar and Ulduar (Heroic) event types
* FEATURE: Patch 3.1 compatible
* FEATURE: Edit tab automatically gives keyboard focus to the Title field
* BUGFIX: "Guild Members Only" checkbox no longer shows up when not in a guild