Google Calendar - Spend less time managing your day & more time enjoying it
24me - Next Generation Personal Assistant
Jorte - Schedule books must be practical and has a good design.
Awesome Cal - Awesome Cal is a Calendar application for your iPhone that you can take anywhere and keep close by to monitor all the upcoming birthdays, festivities, meetings, and more from a single place.
Business Calendar - Powerful and easy to use calendar app for Android including weather, widgets and tasks.
Pocket Informant - Pocket Informant is the Best Calendar app for mac and iOS. Pocket Informant for iOS, Mac desktop, and Android.