ReminderFox is an open source application or website designed to help users manage their tasks and reminders. It integrates with popular calendars and task lists, such as Google Calendar and Mozilla Lightning, to provide users with a single system to manage their tasks. The application allows users to create and edit reminders, send reminders to contacts, and manage and organize tasks into lists. It also provides users with a variety of tools such as customizable views and categories, alarms, notes, and more. Additionally, users can share tasks with other ReminderFox users, sync their ReminderFox tasks with their favorite calendar and task list, and access their reminders from any computer.
I did not see a way to import birthdays.