Nvim is an clone of some of the main features of Notational Velocity as a vim script.
NV/NValt remain one of the best arguments in favour of using OSX. A fast, efficient note-taking system that can be controlled entirely though the keyboard. Its combined search / title bar means you can just tell it what you want and you get the information you need or the ability to create a new note from the same command. Unfortunately the codebase is too heavily dependant on OSX to make a port viable.
A cross-platform clone of it already exists in the form of nvpy, however for various reasons1 it’s not really for me.
Nvim is implemented as a vim script that is compatible with both vim and gvim, so it can be used in both as a gui app and in a terminal and on any platform that runs the requirements2
Currently the codebase is a few defects short of the release version, however it is fully usable as is.