WebCalendar
- A PHP application used to maintain a calendar for one or more persons and for a variety of purposes. In addition, the calendaring system is well documented. [Open Source, GPL]
- http://www.k5n.us/webcalendar.php

Keith Devens PHP Calendar
- A simple, but complete, PHP script to print out a calendar.
- http://keithdevens.com/software/php_calendar

SCA-Calendar
- A PHP5/MySQL or SQLite calendar based on the SCA class library. It supports recurring entries, categories, dynamic holiday calculation and has a sophisticated rights management. [Open source, GPL]
- http://www.project-sca.org/subprojects/sca-calendar-en.html

HIOX Monthly Calendar
- A PHP/Javascript script to show monthly calendar. [Freeware]
- http://www.hscripts.com/scripts/php/calendar.php

PHP Availability Calendar
- A PHP calendar script that shows availability of your rental based on calendar data. [Commercial]
- http://www.merenkov.com/calendar/

MicroCal
- A calendar solution for dating or membership website. It allows running as popup, or being built in page or even in a form in script. [Free with crypted source code and commercial versions]
- http://calendarscripts.info/index.php?action=product&id=1

Active Calendar
- PHP class that generates calendars (month or year view) as HTML tables (XHTML-Valid). The layout can be configured using CSS, and JavaScript is not required. [Open source, LGPL]
- http://freshmeat.net/projects/activecalendar/

Easily Simple Calendar
- Simple PHP calendar script that is easy to customize.
- http://www.easilysimplecalendar.com/

ACal Project
- A PHP calendar project that does not require a database server and is easy to install, setup, and use. [Open source, GPL]
- http://acalproj.sourceforge.net/

PHP Calendar by Cascade
- A customisable PHP 3/4 calendar class.
- http://www.cascade.org.uk/software/php/calendar/index.php

Proverbs Web Calendar
- Shows a month format with a popup window detailing the events of each day as they are clicked on. The title and colors are fully customizable within a single file.
- http://www.proverbs.biz/opensource/calendar.php

Project Based Calendaring System (PBCS)
- An open source web-based system designed to be a useful tool for project managers or planners.
- http://www.pbcs.org/index.php

Schedule Organizer
- Allows a customer to schedule an appointment via a company's homepage.
- http://www.schedule-organizer.de/en/

MyCalendar
- PHP4/MySQL calendar featuring recurring entries, holiday calculations, optional categories, language packs, numerous search and display options.
- http://abledesign.com/programs/MyCalendar/