Basically the same problem as my other site Meetifyr - a group of people figuring out which day to do something on. Everyone votes on which days work best from them.
The difference for Convenely is the calendar view and every event has it's own mailing list. It doesn't update your calendar.
http://www.bookmarks.io/ - working but mothballed.
http://convenely.com - current project, no traffic yet.