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.

Jesús Lopez

The Random Post Scheduler lets you schedule your draft posts in two different ways:
<ol>
<li>Date Range: Schedule your posts within a specific date range, with a minimum interval between publications. </li>
<li>Random Interval: Schedule your posts with a random interval between each publication, regardless of the dates.</li>
</ol>
This plugin is ideal for:
<ul>
<li>Blogs that want to maintain a consistent publishing frequency </li>
<li>Sites with many draft posts that need to be scheduled </li>
<li>Anyone who wants to automate content scheduling</li>
</ul>

Random Post Scheduler

Plugin to schedule WordPress posts with random dates and times within a defined range.

FourNodes Random Post vs Random Post Scheduler