There are many great datepickers out there, but it's pretty difficult to find a decent timepicker.  I'm not the first person to search for such a tool.

Well, there is one that, in my opinion, trumps the rest:  timepickr.   The user can select a valid time in a maximum of two clicks of the mouse and, unlike many other great timepickers, has build in validation to save you from having to write it on your own.

Configuration is easy - here's what I use:

$(function() {
    $('#EventTime').timepickr({
        convention: 12
    });
}); 

This simple code adds a timepickr to the element "EventTime" and uses a 12 hour clock for entry.