Things - Things is an easy to use task manager.
FCorp My Calendar - Manage diary/note, schedule, todo, birthday, etc.
Any.DO - The #1 task management app used by over 11 million people globally, Any.do is your free mobile and online task manager for Android, iPhone, Web and more.
Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.