Electron is the web-based desktop framework that was originally developed for GitHub's Atom editor. It seems to be catching on, so Sindre Sorhus is compiling a list of Electron applications in Awesome Electron.
The list includes Monu by Max Ogden, which is a process monitoring menu bar application for Mac OS X, and some simpler tools like a Gulp task runner.
Sindre has also made generator-electron, a Yeoman generator for Electron applications. To create your own desktop application with Yeoman, just run:
npm install --global generator-electron
It's pretty detailed and tells a story that you don't usually hear: the team looked at weaknesses in their project's design by writing tests. Then they rewrote parts of it using newer techniques, finally converting client-side code to be isomorphic.