LionWiki is minimalist file-based (doesn't need database), templatable, extensible wiki engine which works from just one file (30KB). It's written in PHP. It supports page history, recent changes, interface localization, password protection (both writing pages and seeing) and much more through plugins (Captcha, RSS, syntax for Tables). It's intended for small personal websites, notebooks and other simple applications. Installation is very easy, just copy file to FTP and create a directory.