Joseph Hinson

Do you have a lot of categories and are sick of having a huge list in your sidebar? Want to highlight only a few of them to make your site easier to navigate?
While redesigning WordPress sites for our clients we kept running into this problem over and over. They had a huge list of legacy categories but only wanted to highlight a few of them. We wrote this plugin to allow them to select which categories to show and which categories to initially hide.
All categories are still accessible by a “see all” link at the bottom of the list.
Add the widget to your sidebar to make it live.

Category Expander

Allows WordPress Admins to show only a selected few categories on the sidebar and hide the rest from view until visitor clicks "See All".

jeff_

Articles to Sidebar allow you to put some articles into the sidebar of pages.
When you use WP as a “normal” CMS, you could want to add some custom boxes into the pages’ sidebars. 
Whith “Articles to Sidebar” you can write articles, put them into :
<ul>
<li>a special category (in order to display to all pages)</li>
<li>a category called the same as the current page</li>
<li>both special category and category called the same as the curent page</li>
</ul>
When the article is displayed into the sidebar, the fist images it contains is used to illustrate. 
The displayed content is the article’s excerpt. If there is no excerpt, the extend (before the <code></code> tag) is used and if there is no extend, one is computed (55 first words) and used.
You can choose to put a link to the article or not. That behavior can be chanched for each articles by using a custom boolean var (articles2sidebar_display_link : 1 force link | force no link).
<h3>Versions</h3>
1 first public release 
1.1 better handling of little images ; adding the link to image when present
<h3>Translations</h3>
Actually, there are no translations, but the plugin code is ready for them.

article2sidebar

Articles to Sidebar allow you to put some articles into the sidebar of pages.

Category Expander vs article2sidebar