Teamup Calendar - Cloud-based calendaring using capability URL, application developed in Zurich, Switzerland.
Google Calendar - Spend less time managing your day & more time enjoying it
Campaign Calendar - Campaign Calendar by Bracket Labs builds a marketing calendar from your Salesforce Campaigns.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
ApPHP Calendar - ApPHP Calendar is a PHP calendar script that may be easily integrated and used with various PHP projects, such as schedulers, event, etc.
Microsoft Outlook Calendar - Calendar is a time-management web application by Microsoft.