Xronos Scheduler is a calendaring application intended primarily for schools, but potentially useful for other organisations.
It stores and displays not just the school's timetable (or timetables) but also everything else which is happening within the school, enabling easy retrieval of a tailored schedule for any individual member of staff, pupil, location, service, activity etc. within the school.
What sets it apart from the vast majority of calendar programs (Google Calendar and the like) is that the information which it holds is structured. Rather than having hundreds of separate calendars, it holds just the one calendar, but then allows potentially thousands of different views on it. This is really important in a school - everything which is happening makes use of the same scarce resources (people, places, things) and the commitments need to be held in a single place.
Users (staff, pupils and the general public) see information tailored to their particular requirements. The general public can see only things flagged as being for public consumption; staff and pupils can see their own commitments (timetable + everything else) and suitably authorized users (under the control of the system administrator) can choose what they see.
The data held within Scheduler can be fed out to external calendaring programs, and to hand-held devices. It updates automatically from the school's MIS, and provides automated notification of clashes where events are arriving from different sources.
Installation instructions are also available.
Xronos Scheduler is licensed under the GNU General Public Licence, version 2.