Create an online calendar as part of an online booking script

We require a calendar implemented to our online booking script. The calendar would have similar functionality to iCal, Google Calendar and Outlook. It would form part of our online booking script, whereby when a business signs up to our service and adds employees, each employee would get a calendar as a component of the overall system. They would be able to add custom length appointments with a description for each, and when bookings came in via the system, it would display those bookings on the relevant employee calendar. The appointments on the calendar could also be edited and made recurring. The calendar would be able to be viewed in a daily and weekly format, just like Google Calendar and Outlook. Demonstrated prior creation of an online calendar is strongly preferred for this job! Please write, 'I know calendars' at the start of your pitch so I can be sure you have read this brief.