dev.Fishy

EN:
Adds a simple widget to the sidebar that displays a random posts.
RU:
Добавляет простой виджет в боковую панель сайта, который отображает случайные посты.

RandPost widget

geegood.com

The Random Featured Post plugin allows you to display a random post from a designated category. Ideally this should draw readers landing on your homepage to some of your best posts. The featured post will display the title “Featured Post” (customizable) along with the post’s title, an excerpt and a link to continue to the full post.
<h3>Using it</h3>
Please go here for now for documentation: http://geegood.com/wordpress/

Show Category Posts Fade in/out

The Random Featured Post plugin allows you to display a random post from a designated category as a "featured" post.

RandPost widget vs Show Category Posts Fade in/out