GushWiki was developed with the generous support of an MIT Eloranta Fellowship during summer 2010. The entire wiki, including data, styling and functionality, is contained in a single HTML file and does not require a server to host the wiki.
For small projects and teams looking for a modern method to document their work, this is perfect. Unlike free wiki's that are hosted online, there are no privacy concerns. Just put the wiki html file in a shared Dropbox folder, a folder synced via SVN, or even email it back and forth. To save the wiki just hit Ctrl-S.