Replaces the tagline on your blog with a random tagline selected from a taglines file you provide.
Version 1.2 adds diagnostic information to the settings page. 
Version 1.1 makes the random tagline consistent throughout a single page display.
<h3>The Tagline File</h3>
The tagline file should contain all of the taglines you want to randomly select from. It is return-delimited, ie. there is one tagline per line.

Random Tagline

Replaces the blog tagline with a random tagline from a text file.

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.

Random Tagline vs Custom Taglines