Xoda

Random Post Box is a plugin that lets you place a box anywhere on your blog, with template tag or shortcode, and 
load random posts with an interval and fade effect. It uses jQuery (Ajax) which means that the content is loaded without 
loading the rest of the page. The timings can be set in the admin options-panel.
The template tag is <code><?php random_post_box(); ?></code>. You can also use the shortcode <code>[random-post-box]</code> in a page or post.
<h4>Features</h4>
<ul>
<li>Insert placeholder with template tag</li>
<li>Insert placeholder with shortcode</li>
<li>Set time for displaying the post</li>
<li>Set times for fade in and fade out affect</li>
<li>Exclude or include posts by category</li>
<li>Exclude posts by age (in days)</li>
<li>Use title only</li>
<li>Use post excerpt or bodycontent</li>
<li>Strip tags from body</li>
<li>Show/hide post metadata</li>
</ul>

Random Post Box

The Random Post Box plugin places a box anywhere on the blog, where it loads random posts one-after-the-other.

dyersorg

<a href="http://www.dyers.org/blog/better-blogroll-widget-for-wordpress/#changelog" title="Better Blogroll Change log" rel="nofollow ugc">Changelog</a>
The Better Blogroll widget for WordPress allows you to display a configurable number of random links from your WordPress blogroll. This should help to combat link blindness while still letting you to share the link love with more of your favorite blogs.
Some Features:
<ul>
<li>Links can be sorted randomly, by title, or by rating.</li>
<li>The number of links shown is configurable.</li>
<li>Categories from which links are shown is configurable.</li>
<li>Links can be set to “nofollow” if your links are coming from paid sources.</li>
<li>Capable of Displaying XFN Data.</li>
<li>Displays image links, text links, or both.</li>
<li>Links can be in a single list or separated by category.</li>
<li>Can display each link’s category or rating to its right.</li>
<li>The description of each link appears in a tool tip.</li>
<li>Allows you to show an explanation that the list is a rolling blogroll.</li>
</ul>

Better Blogroll

Allows you to display a configurable number of random links from your Wordpress blogroll

Random Post Box vs Better Blogroll