Freeplane

Freeplane is a free and open source software application for bulding mind maps.

Graphviz

Markdown is allowed here. The short description describes the project briefly, it should not be longer than one or two sentences.

FreeMind2

FreeMind is a premier free mind-mapping software written in Java. A mind map is a diagram used to visually organize information. A mind map is hierarchical and shows relationships among pieces of the whole.