I just came across Pikaday, which looks good and is quite lightweight (around 11kb of JS, minified). Doesn't require jQuery either.
Here's a demo.
A screenshot of the picker:
(source: github.com)
Example using pikaday with timepicker and moment.js
<link rel="stylesheet" href="/pikaday/css/pikaday.css">
<script src="/pikaday/moment.js"></script>
<script src="/pikaday/pikaday.js"></script>
<script>
var timepicker = new Pikaday({
field: document.getElementById('datetimepicker'),
firstDay: 1,
minDate: new Date(2016, 0, 1),
maxDate: new Date(2100, 12, 31),
yearRange: [2016,2100],
showTime: true,
autoClose: false,
use24hour: false,
format: 'MMM Do YYYY, h:mm a'
});
</script>
github.com/owenmead/Pikaday
momentjs.com