ShowMeYourGists.php

<?php
/*
**	Please get this plugin from the repo:
**	https://github.com/SenpaiSilver/ShowMeYourGists
**
**	This paste isn't always up to date.
*/
function embedGistsInPosts($post) {
	$pat = '/<p>(https?:)\/\/gist.github.com\/(.*)\/(.*)<\/p>/mi';
	$sub = '<script src="$1//gist.github.com/$2/$3.js"></script>';
	$post = preg_replace($pat, $sub, $post);
	return ($post);
}
add_action('the_content', 'embedGistsInPosts');
?>