WordPress
WordPress is awesome blogging software, and one of the best things about it is that you can play around with the code reasonably easily! Recently I was wondering how to go about adding my own applications to WordPress without creating a plug-in which is all about filtering existing data. The answer is to create a template page and add any custom SQL/processing into the template PHP. You can use the global $wpdb to access the WordPress Database variable for custom table querying as described here.