Like many schools, we are deeply invested in Microsoft Outlook and Exchange Server. Yet, we struggle with these products’ limited calendaring abilities. We would really like a modern calendaring system that allows users to turn layers on and off for different public resources. Rather than having dozens of individual, mutually exclusive calendars, my users want dozens of layers in a single multi-calendar. Additionally, portability would be key — the ability for a single user to include an item from a public calendar in one’s personal calendar without unnecessary duplication. I have heard of Zimbra but not given it a close look. We must continue to use Outlook, and frankly, we would like to continue to use Exchange if we can, to minimize the amount of change in our system.
Do you know any open-source tools that can layer on top of Exchange to provide these meta-calendaring services?