Name of Addon: ReminderFox
Bottom Line: Reminds you of whatever you ask it to, via a small popup in your status bar.
Why it is Useful:ReminderFox is an extension for Firefox and Thunderbird that displays and manages lists of date-based reminders and ToDo’s. ReminderFox does not seek to be a full-fledged calendar system. In fact, the target audience is anybody that simply wants to remember important dates (birthdays, anniversaries, etc) without having to run an entire calendar application.
Where to find it:
