OS X's Calendar application helps keep you on time for everything. You can use Calendar to track appointments, birthdays, and other important events. You can also subscribe to other people's calendars, or publish your own to share with theirs. In Mavericks Apple has integrated Calendar even more effectively into the OS X ecosystem, linking it to the Maps application so your appointments can also include accurate travel time. Calendar even supports linking to Facebook, so if you have appointments and other important dates linked there, Calendar can remind you.