Content Blocks gives you a reusable & extendable custom post type in plugin form than can be used for a variety of purposes throughout your site.
Great when used with Sizeable Content Tags (
http://wordpress.org/extend/plugins/sizeable-content-tags/).
For more information on Content Blocks, visit the project on GitHub:
http://github.com/szbl/szbl-content-blocks
Extract the zip file and just drop the contents in the wp-content/plugins/ directory of your WordPress installation and then activate the Plugin from Plugins page.