If your Microsoft Dynamics CRM 2011 organization has been upgraded to the 'December Release', also known as Update Rollup 12, and you opted in for the new User Interface (via Settings -> Administration -> Product Updates) or if you started a new trial of Microsoft Dynamics CRM Online after January 15th 2013, you will notice a few things missing from your Workplace, mainly Imports and the Calendar.
How to add the missing calendar
Microsoft packaged these two features within Microsoft Dynamics CRM into a new section called "Tools" alongside with Duplicate Detection and the Service Calendar. The bad news is that the new section is hidden by default. But the good news is that it is simple to show this new section within your workplace. Here's how to add the calendar back:
Navigate to your CRM Options, via the Web Browser's File Tab -> Options or via Microsoft Outlook's File Tab -> CRM -> Options. For this example I am using the Web Browser:
Within Options, click on the "Workplace" tab and check the "Tools" checkbox and click 'OK':
Notice how the Calendar, Imports, Duplicate Detection and the Service Calendar have been added to your workplace.
NOTE: This process needs to be followed by every Microsoft Dynamics CRM User that needs access to the Calendar or any one of these "Tools".