Gist Input Filter

This module provides an input filter to add a gist (from Github) anywhere input filters are accepted. You have the option of replacing the filter tag with a link to the gist or embedding the gist itself.

From Github:

Gist is a simple way to share snippets and pastes with others. All gists are git repositories, so they are automatically versioned, forkable and usable as a git repository

It is by far the easiest way to embed code in your site, with syntax highlighting and all.

To add a gist to a post, simply add [gist:#####] where ##### is the number of your gist. As of 7.x-1.1 and 6.x-1.2, you may also include a specific file within a multi-file gist with [gist:#####:my_file].