We all use calendars. Some digital calendars have a standardized interface called iCalendar (see Wikipedia). An example are Meetup.com Groups or Google Calendar.
Let's dig into one use case: Meetup is great to organize your local meetup. Meetup also has great sharing and API options. They do support embedding the meetup group together with the next meetup. However, there is no out-of-the-box support to embed your schedule to another website.