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.
MediaWiki - MediaWiki is a free software wiki package written in PHP, originally for use on Wikipedia.
Wiki on a Stick - Self-contained desktop wiki
TiddlyWiki - a non-linear personal web notebook
Confluence - Confluence is content collaboration software that changes how modern teams work
ZuluPad - ZuluPad is a notepad on crack.