Plans is a powerful and flexible Web calendar. Its features include recurring events, merged calendars, event icons, custom themes and templates, MS Outlook export, SQL or flat-file data storage, and browser-based management.

Chaussette is a PHP/MySQL Web group calendar using Ajax. With it, friends can share events and chat together.

ACal is a web based event calendar designed in such a way so that anyone can use it. One of the main focuses is to keep things simple. The calendar is written in PHP and starting with ACal 3, PHP 5 is required.

Monket Calendar is coded in HTML, CSS, Javascript, and PHP. It is based on the premise of providing an Apple iCal style interface that is available wherever you are.

Dates is a small, lightweight calendar that shares data with GNOME Evolution. Dates features an innovative, unified, zooming view and is designed for use on hand-held devices, such as the Nokia 770 or the Sharp Zaurus series of PDAs.

Evolution is the GNOME mailer, calendar, contact manager, and communications tool.