A runtime for Node.js apps, Node-WebKit lets you package said apps with a stripped-down copy of Chromium and deliver them on any platform where Node.js and Chromium have been ported (Linux, Mac OS X, and Windows, at least right now). The packaging process couldn't be simpler. You zip up a copy of your Node.js application, add a manifest, and you're done. You even have access to the app window's menus and other platform-native behaviors via Node.js methods and objects.
Cross-platform application deployment has never been easy. A way to build desktop applications with Web technologies, Node-WebKit might well be an alternative to bigger, more cumbersome frameworks.