Calcium provides interactive calendars you can use through your browser. Features include: dynamic calendar merging (events from one calendar can be included in another), multiple views and formats, repeating events, email support, extensive color and font customization, support for full HTML in the event text and calendar headers and footers, popup text associated with any event, searching and filtering, multi-language support, a flexible security model, and more. Calcium is very easy to use, and fully supported by an established company. It runs anywhere that supports Perl CGIs; no non-standard Perl modules are necessary. Full 2-way synchronization with Palm Pilots or MS Outlook is available; iCalendar "subscriptions" are supported too.
Calendars for the Web provides a server based calendar and scheduling application. It allows unlimited users to share unlimted events per calendar. Calendars for the Web comes with a full-featured browser based interface, is completely customizable (sixteen different calendar view types), fully documented, and supports online administration.
OpenGroupware.org is a set of applications for contact, appointment, project, and content management. It is comparable to Exchange and SharePoint. It is accessible using Web interfaces or using local clients via WebDAV, GroupDAV, and CalDAV. Custom applications can be developed using the XML-RPC API. OpenGroupware.org runs on almost every GNU/Linux system.
ttm is a simple but flexible command-line based Perl program for managing lists of tasks. Arbitrary properties can be attached to each task. Standard properties such as `priority', `status' and `categories' are used to provide different ways of viewing the task list. Editing is done with your favourite text editor.
Vanilla is a WikiClone written in REBOL. It is useful for collaboratively working on projects, tracking todo items, managing adresses, and creating Web logs. All page editing takes place in the browser. Vanilla features a simple templating system, a full-featured user and session management system, and an extension architecture for writing simple Web applications in REBOL.
XNotesNG is the next generation of XNotesPlus, a full-featured personal information manager. It is plugin driven and includes a Todo Manager, Calendar Manager, Category Manager, and extensive notes system, including features such as text searching, printing, alarms, date and calendar inserts, and categorization by colored projects.