tstafford

Adds a shortcode to include the content of a file or URL inside of a WordPress page or post.
Example:
Include the following in a page or post: 
[include_file url=http://example.org/somefile.txt]
This would include the content of http://example.org/somefile.txt into your page or post.

include-file

Adds a shortcode to include the content of a file or URL inside of a WordPress page or post.

oltdev

This plugin enables page or post authors to scrape content from mediawiki pages and appending it to their pages. 
It works by scraping content from mediawiki pages by going to a special mediawiki page url.
For example http://en.wikipedia.org/wiki/Wordpress?action=render
The content rendered on the final page or post will always be the newest content, however it is not searchable via regular WordPress search form.
Use case: 
This plugin is great for adding documentation to your site. 
Since wordpress.org is using mediawiki for the codex you could potentially display wordpress codex pages on your site without much effort, just enter the full url of the specific wordpress codex page.
Enjoy

Wiki Append

Append a mediawiki page at the end of the regular wordpress page.

include-file vs Wiki Append