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.

nkuttler

Switch between the backends of your WPMU blogs with just one click. This is probably only useful if you don’t have too many blogs and use all of them yourself. The switch links will be added to your super admin menu.
With the release of WordPress 3.0 I merged several WordPress installs into a single network-enabled WordPress 3.0 install. As I post on all of them I wanted the ability to switch quickly between the backends. This plugin makes that possible
By the way, I use the Ozh admin menu plugin. You might need two clicks to switch if you don’t.
<h4>Support</h4>
Visit the <a href="http://www.nkuttler.de/wordpress/" rel="nofollow ugc">plugin’s home page</a> to leave comments, ask questions, etc.
<h4>My plugins</h4>
<a href="http://www.nkuttler.de/2010/06/07/wpmu-switch-backend/" rel="nofollow ugc">MU fast backend switch</a>: Switch between your MU blog backends with one click
<a href="http://www.nkuttler.de/2010/05/21/record-movies-of-visitors/" rel="nofollow ugc">Visitor Movies for WordPress</a>: Did you ever want to know what your visitors are really doing on your site? Watch them!
<a href="http://www.nkuttler.de/wordpress/nktagcloud/" rel="nofollow ugc">Better tag cloud</a>: I was pretty unhappy with the default WordPress tag cloud widget. This one is more powerful and offers a list HTML markup that is consistent with most other widgets.
<a href="http://www.nkuttler.de/wordpress/nkthemeswitch/" rel="nofollow ugc">Theme switch</a>: I like to tweak my main theme that I use on a variety of blogs. If you have ever done this you know how annoying it can be to break things for visitors of your blog. This plugin allows you to use a different theme than the one used for your visitors when you are logged in.
<a href="http://www.nkuttler.de/wordpress/zero-conf-mail/" rel="nofollow ugc">Zero Conf Mail</a>: Simple mail contact form, the way I like it. No ajax, no bloat. No configuration necessary, but possible.
<a href="http://www.nkuttler.de/wordpress/custom-avatars-for-comments/" rel="nofollow ugc">Custom avatars for comments</a>: Add a personal touch: Your visitors will be able to choose from the avatars you upload to your website for each and every comment they make.
<a href="http://www.nkuttler.de/wordpress/nkmovecomments/" rel="nofollow ugc">Move WordPress comments</a>: This plugin adds a small form to every comment on your blog. The form is only added for admins and allows you to <a href="http://www.nkuttler.de/nkmovecomments/" rel="nofollow ugc">move comments</a> to a different post/page and to fix comment threading.
<a href="http://www.nkuttler.de/wordpress/delete-pending-comments" rel="nofollow ugc">Delete Pending Comments</a>: This is a plugin that lets you delete all pending comments at once. Useful for spam victims.
<a href="http://www.nkuttler.de/wordpress/nksnow/" rel="nofollow ugc">Snow and more</a>: This one lets you see snowflakes, leaves, raindrops, balloons or custom images fall down or float upwards on your blog.
<a href="http://www.nkuttler.de/wordpress/nkfireworks/" rel="nofollow ugc">Fireworks</a>: The name says it all, see fireworks on your blog!
<a href="http://www.rhymebox.de/blog/rhymebox-widget/" rel="nofollow ugc">Rhyming widget</a>: I wrote a little online <a href="http://www.rhymebox.com/" rel="nofollow ugc">rhyming dictionary</a>. This is a widget to search it directly from one of your sidebars.

WPMU fast backend switch

Switch between the backends of your WPMU blogs with one click

Multisite Random Blog Redirect vs WPMU fast backend switch