Teamup Calendar - Cloud-based calendaring using capability URL, application developed in Zurich, Switzerland.
Teamweek - A project management software to help you get the best overview. Plan fast, change plans faster!
Microsoft Hotmail - Collaborative Calendars
Kin Calendar - The simple and connected calendar
VCalendar - VCalendar is an open source Web calendar application for posting and maintaining events and schedules online.
Google Calendar - Spend less time managing your day & more time enjoying it