iCalendar is a widely-used data format for representing and exchanging calendaring and scheduling information independent of any particular calendar service or protocol.
iCalendar is a data format for representing and exchanging calendaring and scheduling information such as events, to-dos, journal entries, and free/busy information, independent of any particular calendar service or protocol.
Used and supported by many products, including google-calendar, Apple's iCal and Microsoft outlook.
- Based on RFC 5545: http://tools.ietf.org/html/rfc5545
- Successor of vcalendar (Fun fact: iCalendar actually has version number 2.0)
- A website with an explanation of the specification, as well as a validator: http://icalendar.org
- General info: http://en.wikipedia.org/wiki/ICalendar
- App support: http://en.wikipedia.org/wiki/List_of_applications_with_iCalendar_support