iCal is an elegant personal calendar application that lets you keep track of your appointments and events with multiple calendars featuring at-a-glance views of upcoming activities by day, week or month. iCal lets you create separate color-coded calendars for your home, school and work schedules, and it lets you view all your different calendars at the same time from within a single unified window. You can use iCal to remind you of time commitments, keep track of your deadlines, send and receive email and text-message notifications, set alarms, and even create and prioritize To Do lists.
Tasks is built on PHP and MySQL. It features a dynamic hierarchical view of your tasks, scheduling due dates, and associating URLs with and uploading and attaching files to tasks. RSS Feeds and iCalendars of your tasks are available. There is a mobile interface for use with a Web-enabled PDA or cell phone.
Copper is a Web-based project management software tool designed to help creative teams manage clients, projects, tasks, files, budgets, and events. It has an HTML/AJAX front end. It is available with full source for a licence fee or as a SAAS hosted service (compatible with iPhone, but available via PC/Mac/Linux and a Web browser).
When is an extremely simple personal calendar program, aimed at the Unix geek who wants something minimalistic. It can keep track of things you need to do on particular dates. It's a very short and simple program, so you can easily tinker with it yourself. It doesn't depend on any libraries, so it's easy to install. You should be able to install it on any system where Perl is available, even if you don't have privileges for installing libraries. Its file format is a simple text file, which you can edit in your favorite editor.
MightyCal is a powerful calendar/schedule building program which aims to be the MS Access of the Web calendaring world. It provides an easy-to-use administration interface for developing custom calendars of many types, from simple event bulletin boards, to schedulers of human/physical resource availability, to schedulers which automatically take programmed actions. Users of a MightyCal site can choose to view calendars in a wide variety of formats on numerous devices, from standard HTML to PDF and WML. MightyCal's architecture combines the object-oriented web development of Zope with the XML transformation capabilities of Cocoon.
My Signup Sheet is a simple Web-based application that allows visitors to sign up for events. It is intended to be used for teachers and organizations wishing to allow users to sign up for events. The admin may specify the events, number of seats available, and information required from each user. The admin can also specify a unique email address for each event to be notified when someone signs up.
IceWM Control Panel is a full-featured, GTK-based control panel for IceWM. It features an IceWM theme designer, Ice Sound Manager (for sound events), IcePref2, and tools to manage desktop wallpaper, cursors, keys, window options, and more. IceWM Control Panel has a familiar, Windows-like Control Panel user interface.