The Calendar
In the Calendar you have the ability to manage all your appointments with other users. If you give other people permission to do so, people can invite you for an appointment by placing it in your calendar or vice versa.
The calendar can be viewed per day, a few days, week or a month.
Some examples:

Above you see the default view of a calendar that can show one, two, five, seven or fourteen days. The grid is confgurable for one hour, half an hour or 15 minutes per line.
The month view:

