Wiki on a Stick - Self-contained desktop wiki
ConnectedText - ConnectedText is a powerful but simple information management system.
Woas - Complete wiki in a single HTML file, forked from Wiki on a Stick.
TiddlyWiki - a non-linear personal web notebook
Ultra Recall - "Ultra Recall is personal information, knowledge, and document organizer software for...
Zim Wiki - Zim is a graphical text editor used to maintain a collection of wiki pages. Each page can contain links to other pages, simple formatting and images.