This plugin adds a new table to your WordPress database so you can save any number of short (100 character) quotations, comments, sayings, or anything you want. Then you can have them display in your site’s header (or anywhere you choose) by adding a function to your theme’s template file.

David’s Pithy Quotes

Allows you to save short quotations / sayings / comments to a database table and then display them randomly on your site.

Brian Zeligson

WP Custom Taglines adds a meta box to your posts and pages with two options, Enable Custom Tagline, and Custom Tagline Content. Checking 
“Enable Custom Tagline” will cause your site to display the contents of the “Custom Tagline Contents” field on your site when that post or 
page is viewed, instead of the sitewide tagline.
Check out http://www.workinginboxershorts.com for more plugins, for support or questions, or to contribute code.

Custom Taglines

WP Custom Taglines allows you to specify a custom tagline for each post or page that will override the sitewide tagline for that post or page.

David’s Pithy Quotes vs Custom Taglines