Rob Saurini

It’s simple enough to embed a Gist, but the default embedded Gist behavior isn’t as easy to read as it could be. I’ve added line numbers and alternating line colors in order to give the gist maximum readability.
Use
<ul>
<li>You can use the shortcode [pretty_gist id=”gist_id“] to embed the pretty gist directly into a post</li>
<li>You have the option to change the default colors in Settings > Pretty Gists</li>
</ul>

Pretty Gists

Gives you the ability to add Github Gists to your site decorated with line numbes and alternating line color.

Claudio Sanches

This plugin adds Github Gists in your posts via shortcode.
Examples
Add a full gist:
<pre><code>[gist id="3837669"]
</code></pre>
Add a specific file in a gist:
<pre><code>[gist id="3837669" file="index.php"]
</code></pre>
<h3>License</h3>
Gist GitHub Shortcode is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published 
by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
Gist GitHub Shortcode is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of 
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with Gist GitHub Shortcode. If not, see <a href="http://www.gnu.org/licenses/" rel="nofollow ugc">http://www.gnu.org/licenses/</a>.

Gist GitHub Shortcode

Adds Github Gists in your posts via shortcode

Pretty Gists vs Gist GitHub Shortcode