Kin Calendar - The simple and connected calendar
Google Calendar - Spend less time managing your day & more time enjoying it
Teamup Calendar - Cloud-based calendaring using capability URL, application developed in Zurich, Switzerland.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Teamweek - A project management software to help you get the best overview. Plan fast, change plans faster!
iCal - In Calendar on your Mac, subscribe to calendars published or shared by others.