I've used a number of themes on this site in recent times for one reason or another but one thing you can be sure of is I will tweak the heck out of whatever theme I'm using at the moment. Part of the fun of using a new theme is ripping it apart then putting it back together again after having put your own stamp on it.
Some of the things I have done to this theme include creating images pulled from custom fields which are displayed on the home page, building a horizontal navigation menu to display categories and constructing a "more news from this category" module which is shown on single post pages. In this post I'll show you how to do the latter.
In your favourite plain text editor open the file that generates your sidebar and insert the following ...
<?php global $post;
$categories = get_the_category();
foreach ($categories as $category) :
?>
<h3>More News From This Category</h3>
<ul>
<?php
$posts = get_posts('numberposts=20&category='. $category->term_id);
foreach($posts as $post) :
?>
<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
<?php endforeach; ?>
<li><strong><a href="<?php echo get_category_link($category->term_id);?>" title="View all posts filed under <?php echo $category->name; ?>">ARCHIVE FOR '<?php echo $category->name; ?>' CATEGORY »</a></strong></li>
<?php endforeach; ?>
</ul>
What this will do is create a list of the 20 most recent posts from whatever category the post currently being displayed on single.php is from. For instance, if you're reading a post from the Automobile category the sidebar will display the 20 most recent entries from that category complete with a link to the topic archives. Obviously you can change the number of posts you want shown.
As a further enhancement, on this site I created a sidebar to hold this content which is exclusive to single.php. In other words, the sidebar appearing on single post pages will not appear elsewhere on this site.