I would be interest in hearing of any churches that do this in conjunction with shut-in ministries. This is usually done by relating the church to the community in which it is located. Better sites generally offer more information about each event. Some look like actual monthly calendars, some offer a weekly view and some are lists of events in chronological order. PDF is easier for most churches to use, but is less accessible than standard web pages.
Community links are also popular additions.
This is not particularly common as far as I have seen. They are seen more frequently on smaller web sites. But the ones I've seen have been nice additions to their sites. They often have letter from missionaries and information about the countries involved. They often include a means of contacting those involved.