Random Related Posts is a WordPress plugin by Fubra and ray.viljoen that provides a sidebar widget with customisable title and number of related posts to display.
Styled version of the widget
The widget will display a random list of x number of posts ( selected in widget options ) together with a small tag including the publish date and author. If used outside of a specific category the widget will default to all categories, whilst still displaying the selected number of random posts.
Download and info: http://wordpress.org/extend/plugins/random-related-posts/
