WP: related posts by category

related_posts_category.php

<?php 

$orig_post = $post;
global $post;
$categories = get_the_category($post->ID);
if ($categories) {
  $category_ids = array();
	foreach($categories as $individual_category) $category_ids[] = $individual_category->term_id;
	
	$category_name = $individual_category->name;
	$category_link = get_category_link($individual_category->term_id );

	$args=array(
		'category__in' => $category_ids,
		'post__not_in' => array($post->ID),
		'posts_per_page' => 2, // Number of related posts that will be shown.
		'ignore_sticky_posts' => 1
	);

	$my_query = new wp_query( $args );
	if( $my_query->have_posts() ) {
		echo '<div class="related_posts_container">';
		echo '<div class="widget-title"><a href="' . $category_link . '">Other ' . $category_name . ' Projects</a></div>';
		echo '<ul class="related_posts">';
		while( $my_query->have_posts() ) {
			$my_query->the_post();
	?>

				<li class="hentry">
					<div class="related_thumb">
						<a href="<? the_permalink()?>" rel="bookmark" title="<?php the_title(); ?>">
							<?php the_post_thumbnail('thumbnail'); ?>
						</a>
					</div>
					<div class="related_content">
						<h3 class="entry-title">
							<a href="<? the_permalink()?>" rel="bookmark" title="<?php the_title(); ?>">
								<?php the_title(); ?>
							</a>
						</h3>
					</div>
				</li>
	<?php
		}
		echo '</ul>';
		echo '<div class="related_posts_more"><a href="' . $category_link . '">See More ' . $category_name . ' Projects &raquo;</a></div>';
		echo '</div>';
	}
}
$post = $orig_post;
wp_reset_query(); 

?>