User-defined Order By

Out of the box, no. But you could create a dropdown menu that reloads the page but adds a GET variable (ex: yoursite.com/?post_sort=new), then use the built-in filters to modify the query based on that variable.

Very similar to this tutorial ( http://www.billerickson.net/shortcut-args-for-display-posts-shortcode/ ) except instead of looking for an argument in the shortcode itself, look in the page’s $_GET variable.

Ex:

if( isset( $_GET[‘post_sort’] ) && ‘new’ == $_GET[‘post_sort’] ) {
$args[‘orderby’] = ‘post_date’;
}
`