I offer the JS appointment script - jQuery Appointment Maker
easy interface, simply by selecting appointment, date, time and clicking a button.
You can define your own email content template (back end script needed. eg. PHP script - NOT INCLUDED ), so you
don’t have to type any content for email each time. Even more, you can
block specific dates to inform people those days are not available for appointments.
jQuery Appointment Maker can be used as a simple online booking/reservation system as well, it is very user-friendly.
Demo: Demo jQuery Appointment Maker
It's very easy to install. You can easily install it on your website.
(I offer only the script. Installation by yourself. For this reason, take a look to the demo site and read the instructions)