Recently I experimented with a jQuery event calendar on our Booking System. Our previous version uses ASP.NET to build the booking chart as a whole on the server and then renders the lot to the browser. It was a bit slow and clunky, but worked.
I wanted to have a PHP version of the Room Booking System so did a quick port from the ASP.NET C# to PHP, and then I dropped the jQuery fullcalendar component on the page. I used a web service for the data which was still written in C# against a Microsoft SQLServer database.