Those important dates in your life, in which you want to plan in detail, this is a good way to do it with Sunbird.
ReminderFox displays and manages lists of reminders and ToDo's. ReminderFox makes sure you remember all of your important dates via easy-to-use lists, alerts, and alarms, right in your browser without the need for a separate calendar program.
FoxClocks shows times around the world - or just your local time - at the bottom of your browser. It deals with daylight saving time so you don't have to.
Transliterator allows as-you-type conversion of text from one alphabet to another, as well as transliteration/detransliteration anywhere within documents.