ReminderFox - Reminder in your Firefox

ReminderFox is an extension that displays and manages lists of date-based reminders and ToDo’s. ReminderFox does not seek to be a full-fledged calendar system. This extension want to give you a simple reminder to make you remember important date like birthdays, anniversaries, events, etc.
ReminderFox adds an icon to your application, a ribbon tied into a reminder-knot. By default this is shown in the status bar, but can be changed via the options. You can create a Quick Alarm via the status bar icon’s context menu. This allows you to quickly set an alarm to be reminded of something that will happen shortly.