The Calendar module of Rainmail Groupware consists of the tools required for time management. 

The features of Calendar are:

• Views: 1-Day, 5-days, 7-Days, Monthly and List Views of appointments entries
• Appointments: Users can schedule meetings, invite participants and respond to meeting invitations from other users. This feature includes the capability to detect scheduling conflicts
• Check Availability: This feature can be used to check availability of other participants while scheduling
• Reminders: Set automatic reminders for upcoming meetings
• Recurring events: Users can schedule repeating events and set an end date for the recurrence
• Import/Export Calendar: Users can import/export calendars from/to other calendar applications in iCalendar file format
• Permissions: Users can share calendars with other users and grant permissions at the desired level