Using the code downloaded from NuGet threw an error because $ was not defined. To solve this I added a script tag to PartialViewDemo.html, so my file is now
Code:
<div id="result"></div>
<script src="~/Scripts/jquery-1.10.2.js"></script>
<script type="text/javascript">
$(function () {
$('#result').load('/sample/message');
});
</script>
Which makes it work!