Stephanie Leary

This widget will list random posts from a chosen category. You can choose how many posts to display, and whether to show the excerpt or the full content in addition to the post title. You may also link the widget title to the category archive if you like.
<h3>Translations</h3>
Belorussian (be_BY) by <a href="http://fatcow.com" rel="nofollow ugc">FatCow</a>. 
Romanian (ro_RO) by Web Geek Science (<a href="http://webhostinggeeks.com/" rel="nofollow ugc">Web 
Hosting Geeks</a>)
If you would like to send me a translation, please write to me through <a href="http://sillybean.net/about/contact/" rel="nofollow ugc">my contact page</a>. Let me know which plugin you’ve translated and how you would like to be credited. I will write you back so you can attach the files in your reply.

Random Posts from Category

A widget that lists random posts from a chosen category.

Four Nodes

Simple plugin to display random posts on your wordpress blog. Plugin provides a widget to display random posts in sidebar. 
Also comes with a shortcode [randomposts] to include on pages.
<ul>
<li>Easy to install</li>
<li>Picks Random Posts</li>
<li>Ability to select from specific category</li>
<li>Limit number of posts</li>
<li>Shortcode support</li>
</ul>

FourNodes Random Post

Displays Random wordpress posts in a sidebar widget. Also, provides shortcode to display random posts on pages.

Random Posts from Category vs FourNodes Random Post