Solistic Calendar is a Web diary and calendar system written in Perl using a MySQL database backend. A key aim is to produce a high quality program built within a standard Perl installation using minimal external packages. Other design aims include easy and inexpensive installation.
google-rfc-2445 is a Java implementation of RFC 2445 recurrence rules. RFC 2445 describes a scheme for calendar interoperability. This project implements core parts of RFC 2445, including a parser for recurrence rules and date lists and a mechanism for evaluating recurrence rules.
The Darwin Calendar Server is a standards-compliant server that allows multiple users to collaboratively share calendaring information. It provides a shared location on the network to store schedules, and allows users to send each other and manage invitations. In order to provide interoperability with multiple calendaring clients, the server implements the CalDAV protocol, which is an extension of WebDAV, which is in turn an extension of HTTP.
Nomad PIM is an extensible personal information manager. It allows you to keep track of your personal data and provides modules for notes, schedule, contacts, money, diary, and timetracking. It is implemented as an Eclipse RCP application. Like Eclipse, it provides extension points for extensions by additional plugins.