Some time ago I encountered mdwiki, a Wiki which is processed entirely client-side. In short:

1. Download mdwiki.html, put it in the root of your site, and rename it to index.html
2. Add index.md which you use as your index page. Write content in your favorite formatting syntax, Markdown :-)
3. Optionally add a navigation.md for a navigation bar.
4. Add any other Markdown file.

It doesn't have many features but in my opinion it doesn't have to. It's great for quickly publishing ideas or content without bothering too much yet with layout and looks. Now, that doesn't mean it's not possible to make nice looking sites as can be seen in the examples. Also, features can be added using gimmicks. Examples of added functionality are the parsing of equations, embedding Google Maps and YouTube video's.