A quick plugin to get the segments of a supplied URL.

{{ segment num="2" url="/blog/categories/whiskey" }}
Outputs: categories

{{ segment num="1" url="/blog/categories/whiskey" }}
Outputs: blog

{{ segment url="/blog/categories/whiskey" }}
Outputs: blog  
(The num parameter defaults to 1)

Use a negative num to get segments from the end of the URL.

{{ segment num="-1" url="/blog/categories/whiskey" }}
Outputs: categories

{{ segment num="-2" url="/blog/categories/whiskey" }}
Outputs: blog

{{ segment url="/blog/categories/whiskey" }}
Outputs: blog

Use segment:url and segment:parent_url to get the full url of segments.
(Note: url will default to current_url for this tag)

{{ segment:url num="2" url="/blog/categories/whiskey" }}
Outputs: /blog/categories

{{ segment:url num="1" url="/blog/categories/whiskey" }}
Outputs: /blog

{{ segment num="-1" url="/blog/categories/whiskey" }}
Outputs: /blog/categories

{{ segment num="-2" url="/blog/categories/whiskey" }}
Outputs: /blog

{{ segment:parent_url url="/blog/categories/whiskey" }}
Outputs: /blog/categories