List Popular Posts By Comment Count http://wpsites.net/wordpress-tips/fetch-display-a-list-of-popular-posts-by-comment-count/

functions.php

add_action ( 'genesis_entry_footer', 'popular_posts_after_content' );
function popular_posts_after_content() {
if ( is_singular('post') ) {
    get_template_part( 'wpsites' ); 
}}

style.css

.after-entry {
	background-color: #f5f5f5;
	margin: 25px 0px;
	margin: 2.5rem 0rem;
        padding: 40px;
	padding: 4rem;
}

.after-entry li {
	margin-bottom: 6px;
	margin-bottom: 0.6rem;
}

wpsites.php

<?php 
/**
 * @author    Brad Dalton
 * @example   http://wpsites.net/wordpress-tips/fetch-display-a-list-of-popular-posts-by-comment-count/
 * @copyright 2014 WP Sites
 */
// Your Custom Query
$sticky = get_option( 'sticky_posts' );

$args = array(
	'orderby' => 'comment_count',
	'posts_per_page' => 3,
	'post__not_in' => $sticky
);
$popular_posts = new WP_Query( $args ); 

// Your Custom Loop
    if ( $popular_posts->have_posts() ) {

        echo '<div class="after-entry"><ul>';
		
	while ( $popular_posts->have_posts() ) {
	
		$popular_posts->the_post();
		
		echo '<li><a href="' . esc_url( get_permalink() ) . '" rel="bookmark">' . get_the_title() . '</a></li>';
	}
        echo '</ul></div>';
} else {
	  echo '<div class="after-entry">No posts found for this query.</div>';
}

wp_reset_postdata();