DAViCal is a server implementation of the CalDAV protocol for storing calendaring resources (in iCalendar format) on a remote shared server. An increasing number of calendar clients support the maintenance of shared remote calendars through CalDAV including Mozilla Calendar (Sunbird/Lightning), Evolution, Mulberry, Chandler, and various other closed-source products such as Apple's iCal and iPhone. DAViCal supports basic delegation of read/write access among calendar users, multiple users or clients reading and writing the same calendar entries over time, and scheduling of meetings with free/busy time displayed.
Tine 2.0 is a Web-based groupware solution that focuses on usability and correctness. To achieve these goals, the project uses usability experts and covers most of the code by unit tests. It contains support for contacts, tasks, calendar, email, CRM, VoIP integration, a time tracker, ActiveSync, and a flexible rights management system.
todoyu is a powerful project and task management system. The core features are project handling, time tracking, time sheets, resource management, calendar, customizable reporting, keeping track of communication and decisions, invoicing directly from tracked time, and address management of customers and employees. It improves billing accuracy and timeliness, and removes risk from the billing process. A todoyu customer's clients get visibility into the project work done on their behalf. The system is extensible with additional modules. The system is completely Web based and translated in 12 languages.