Lately I've discovered PmWiki. The default skin is butt-ugly, the installation is quite complicated, but it's definitely the most awesome piece of software I've seen in ages. For a flat files wiki, it's blazing fast (much more than DokuWiki, in my experience). It's also incredibly versatile. Once you understand how it works, you can script quite easily any kind of display for any page and customise everything very precisely.
My current web host, Planethoster, seems unable to update PHP to an acceptable version. They go with CPanel releases, and CPanel seems very slow, because after more than one year, I still can't run the latest version of Anchor, which is a nifty minimal CMS. Hence the idea of switching to PmWiki in a bloggish flavor (instead of finishing my Twine game, of course). Seriously, how could you not love a software called Patrick Michaud Wiki?