webvolution

A playful plugin with several options to pull a joke/prank on your friends. Guaranteed to work on your WordPress website regardless of theme, plugin or version of WordPress.
Types of pranks:
<ul>
<li>B&W – Turns website into black and white like the old days.</li>
<li>Upside Down – Turns website upside-down.</li>
<li>Hide All Odd Numbered Paragraphs – Self explanatory, come on.</li>
<li>Blurry – Turns website so blurry even eye-glasses won’t help.</li>
<li>Poop Emoji – Puts a poop emoji in upper left of the page.</li>
<li>Comics Sans – Turns text to use the Comic Sans font.</li>
<li>Insanely Large Text – Makes fonts larger for those who have really really bad eye-sight.</li>
</ul>
Terms:
<ul>
<li>You are free to do whatever you want with the plugin, but you are liable for any and all damages and legal ramification resulting from the plugin. </li>
<li>I am not liable for anything.</li>
</ul>

WP Pranks

A playful plugin with several options to pull a joke/prank on your friends.

Brooke.

Adds Cornify (cornify.com) to your WordPress. After five seconds of inactivity the site will show unicorns 
to the visitor until they interact with the site again. This was developed primarily as an April fools joke.

WP Pranks vs Cornify for WordPress