GitHub Gist WordPress Plugin allows you to embed <a href="http://gist.github.com" rel="nofollow ugc">GitHub Gist</a> snippets with a [gist] tag, instead of copying and pasting HTML. For example, to embed the <a href="http://gist.github.com/447298.js?file=github_gist_wordpress_plugin_test.txt" rel="nofollow ugc">github_gist_wordpress_plugin_test.txt</a> file from <a href="http://gist.github.com/447298.js" rel="nofollow ugc">gist: 447298</a>, fill in the id and file attributes in the [gist] tag:
[gist id=447298 file=github_gist_wordpress_plugin_test.txt]
or
copy the embedding JavaScript code from GitHub and directly paste it in the body of the [gist] tag:
[gist]<code><script src="http://gist.github.com/447298.js?file=github_gist_wordpress_plugin_test.txt"></script></code>[/gist].
The [gist] tag also expands the content of the embedded Gist and wraps it with “<code><noscript><code><pre></code>” so that search engine spiders, users with javascript disabled and users reading your blog through RSS will still see your code in a blog entry.

GitHub Gist WordPress Plugin

GitHub Gist Wordpress Plugin allows you to embed GitHub Gist snippets with a [gist] tag, instead of copying and pasting HTML.

dflydev

This project is available for forking on GitHub:
<ul>
<li>https://github.com/dflydev/embed-github-gist</li>
</ul>
Embed <a href="http://github.com/" rel="nofollow ugc">GitHub</a> <a href="http://gist.github.com" rel="nofollow ugc">Gists</a> into 
WordPress. Provides a shortcode for posts and pages but also has the ability 
to embed by hand in the event that a Gist needs to be embedded somewhere in 
the page that does not pass through the shortcode filters.
Examples:
<pre><code>[gist id=546764]
[gist id=546764 file=file.txt]
[gist id=546764 file=file.txt bump=1]
[gist]http://gist.github.com/546764[/gist]
</code></pre>
Cache is implemented with the Transients API to minimize delay on loading 
content. Default TTL (time to live) is 86400 seconds or one day.
<h4>Upcoming features:</h4>
<ul>
<li>Option for setting default TTL</li>
<li>Option to bypass cache entirely</li>
<li>Implement admin interface to control options</li>
</ul>

GitHub Gist WordPress Plugin vs Embed GitHub Gist