Open Source Calendar

Choosing an open calendar manager
When choosing group calendaring and scheduling software, many organizations adopt one of the well-established commercial packages like Microsoft Exchange and Outlook, Lotus Notes, or Novell GroupWise. Their perceived simplicity is appealing: you don't have to think about file formats or write configuration files for server software. However, by choosing an application that is built to comply with Internet standards, you can eliminate the risk of being locked into a client whose features don't meet your organization's needs, while maximizing the flexibility and interoperability of your calendaring software.
Deserve an active calendar
Trumba Calendar is a comprehensive web-based calendar publishing platform that encourages customers to interact with your events. Trumba calendars engage website visitors, improve event promotion, and can increase event attendance.
Benefits
Unlike typical passive calendars, Trumba calendars are interactive, easy to create and update, professionally designed, and support RSS and iCal feeds as well as the ability to subscribe to email updates.
Features: An intuitive authoring environment makes it easy to create, update, and publish professional-looking, active calendars.
Open Source Calendar/Alarm/Planner
I did a little searching and I found Rainlendar. It's a open source calendar with a todo list, eventlist, pop up reminder (you can also use a wav file for alarm). It has lots of features and it looks pretty easy to skin. You can send some commands (!Bangs) to it but not very many. We would probably need a plugin to edit the todo list and the event list. Anyway it's open source so maybe one of you coders can take a look at it.
UW Calendar Project
The UW Calendar project is building an open-source calendaring system for higher education. UW Calendar will support personal, public and group events, use existing open standards, and support web-based and other forms of access, including uPortal integration. People affiliated with a college or university typically must keep track of a multitude of calendars. Consider Joan, a graduate student at a university. Joan is taking three classes and working with a research group. To keep track of all the events in her day, Joan must follow the university's academic calendar, her department's calendar (for colloquia and seminars), a calendar for each of her three classes, the calendar for her research group, and her private calendar (for dental check-ups, etc.).
An open-source calendar system
To overcome these obstacles, we propose to build an open calendar system, where as much of the system is open to change from the university community (and beyond) as possible:
1.The code will be open-source. This allows our userbase, which contains many people with computer skills, to find and fix bugs, work on desired features, and suggest and implement completely new features. In addition, because the userbase can participate in changing the application, we will be more likely to add the features most desired by the users first.
2. We will allow events to be added by anyone with a UWNetID. Allowing events to be added anonymously is undoubtedly a bad idea, but we anticipate that forcing people to sign their submissions should prevent most abuses (The Stanford Calendus project is another calendar that allows users to enter events with a campus computer ID). This is somewhat analogous to the open-source programming model, although not exactly: events could be added without a filter, while code is always reviewed before added.
Zimbra's Open-Source Shared Calendar
Zimbra Inc. on Tuesday launched what it claims is the first open-source group scheduling calendar-and with it comes the first publicly available release of its Network Edition, targeted at enterprises. In addition, the company's self-named collaboration suite now supports RSS and Atom feeds, online backup and recovery, hierarchical storage management and clustering for high availability. The startup came out of stealth mode when it launched its Zimbra Collaboration Suite at Web 2.0 in September. The new calendar capability in Zimbra's Beta 2 version includes group scheduling with free/busy indication; the ability to import external calendars in .ics format; a multi-calendar view that allows users to view all calendars to which they have access and to overlay each calendar in different colors; delegated access, such as for executive administrators; time zones and recurrences; and graphical layout that includes drag-and-drop capability.
Web Calendar
WebCalendar is a PHP-based calendar application that can be configured as a single-user calendar, a multi-user calendar for groups of users, or as an event calendar viewable by visitors. MySQL, PostgreSQL, Oracle, DB2, Interbase, MS SQL Server, or ODBC is required. WebCalendar can be setup in a variety of ways, such as...
* A schedule management system for a single person
* A schedule management system for a group of people, allowing one or more assistants to manage the calendar of another user
* An events schedule that anyone can view, allowing visitors to submit new events
* A calendar server that can be viewed with iCalendar-compliant calendar applications like Mozilla Sunbird, Apple iCal or GNOME
Evolution or RSS-enabled applications like Firefox, Thunderbird, RSSOwl, FeedDemon, or BlogExpress.
VCalendar is an open source web calendar
VCalendar (Virtual Calendar) is a web-based application for posting and maintaining events and schedules online, in calendar format. The data is stored in a database centrally on a web server and users need just a web browser to access the VCalendar. No local software needs to be installed on the client machine and all web browsers available are supported. Some of the advanced features of VCalendar include:
* Localization features, with initial Internationalization in English and Russian, with language selectable by end-users
* Dynamic CCS (stylesheet) styles, selectable by end-users
* Annual, monthly, weekly and daily calendar views
* Multiple categories for classifying calendar events
* Recurring and all-day events
* Role-based user permissions and calendar configuration
Creating an Event Calendar
I have recently (both personally and professionally) found it necessary to implement a calendar within a web application. I roamed all of my favorite web developer sites for a component that offered what I needed and did not find anything very interesting. The best example I found is at my second favorite ASP site (second only to 4 Guys, which is of course my favorite), ASP 101. They offer a great calendar app, but it does not have very much functionality. My calendar needed to have current events that were added and edited by registered users, so I took their code and make a few modifications.
Open source institutional calendar system
Bedework is an open-source, institutional calendar system for higher education designed to conform to current calendaring standards. Built in Java, Bedework has a centralized server architecture allowing immediate update of public and personal information. Based on version 2 of the UW Calendar, it has been rearchitected and reimplemented to support many new features. The Open Group brought the Federated Free/Busy challenge to CalConnect, the calendaring and scheduling consortium, of which RPI is a member. CalConnect agreed to partner with The Open Group on the challenge, and RPI volunteered to facilitate the demo using Bedework and Bedework derived code.