TimeTune - TimeTune improves your daily routine and allows you do more things with your time.
Day by Day Organizer - Time management app that combines Google Calendar and Google Tasks and enhances their features.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Calendar Lock PEA - Calendar Lock PEA is an encrypted desktop calendar with a day, week and month view. The shown calendars are never stored unencrypted on your disk, but exist only in the RAM. Platform-independent, Open Source, no installation or registration required.
Google Calendar - Spend less time managing your day & more time enjoying it
Business Calendar - Powerful and easy to use calendar app for Android including weather, widgets and tasks.