Random Content
by Jeremy Green on WordPress.org

Adding the widget to a sidebar.
This plugin allows you to display random content anywhere on your site using a shortcode or widget. You can group your random content together, allowing you to display different content in multiple locations throughout your site.
The content is added via a custom post type, so you have full access to the tinyMCE editor. This allows you to easily add images, text, and links to your random content.
Using a widget
- Navigate to Appearance->Widgets and add the Random Content widget to a sidebar.
 - Select a group from the dropdown. If you don’t create a group, the widget will use all entries.
 
Using a shortcode
Place the shortcode [random_content] anywhere on a post or page.
To choose entries from a specific group, add the group_id parameter. For example, [random_content group_id="64"].
To specify the number of posts to show, add the num_posts parameter. For example, [random_content group_id="13" num_posts="3"].