tiredofit

Allows you to randomly visit a blog in your multisite network by appending ?randomblog at the end of your URL string. 
You can exclude by blog ID, mature or public status, and even change the string to whatever you like. 
View a working demo at <a href="http://www.bicycletouringhub.com?randomblog" rel="nofollow ugc">http://www.bicycletouringhub.com?randomblog</a>
<h3>Contact and Credits</h3>
Written by Dave Conroy (<a href="http://www.tiredofit.ca/?ms-random-blog" rel="nofollow ugc">www.tiredofit.ca</a>, e-mail ‘dave’ at ‘tiredofit dot ca’), 2012-02. 
Written inside of a tent while he bicycles the world for <a href="http://www.bicycletouringhub.com" rel="nofollow ugc">www.bicycletouringhub.com</a>

Multisite Random Blog Redirect

Allows you to randomly visit a blog in your multisite network by appending ?randomblog at the end of your URL string.

jwpegram

Schedule Random Post Time adds a button to the post, page and comments that adds a button allowing you to generate a random date. This plugin is useful for us lazy people that would rather not take the time trying to decide what date and time in the future to schedule a post for. Simply click the button and let it decide for you.
rDate button will be diplayed:
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<li>
When editing the date and time on a Post
</li>
<li>
When editing the date and time on a Page
</li>
<li>
When editing the date and time on a Comment
</li>
<li>
When quick editing a Post
</li>
<li>
When quick editing a Page
</li>
</ul>

Schedule Random Date/Time Button

Adds a Random Date button when editing a Post, Page or Comment.

Multisite Random Blog Redirect vs Schedule Random Date/Time Button