WpRecipes.com - Daily recipes to cook with WordPress

To achieve this recipe, simply paste the following code on he sidebar.php file of your theme:

<?php
query_posts(array('orderby' => 'rand', 'showposts' => 1));
if (have_posts()) :
     while (have_posts()) : the_post();
         the_title();
         the_excerpt();
     endwhile;
endif; ?>

That's all. Your sidebar will display a random post on each of your blog pages.