Gnote is a simple desktop note-taking application for GNOME.
Easy to use, but with potential to help you organize the ideas and
information you deal with every day. Using a
WikiWiki-like linking system, organizing ideas is as simple as typing
a name. Branching an idea off is easy as pressing the Link button. And
links between your ideas won't break, even when renaming and
reorganizing them.

This is a clone of Tomboy, in C++.