Here's an interesting idea to ponder - running Node.js app's inside a web browser. This video is by two developer evangelist dudes working on the Chrome web browser as well as ChromeOS, and it shows running Node.js apps in a browser. The rationale they give is that because Chrome and ChromeOS runs "applications" inside a web browser, it could be useful to use Express (for example) running inside the browser to build such an application. That means running a web server inside the web browser to run an application inside that same browser. Head hurt yet?
The technology under the covers is Browserify ... rather than porting the proper Node.js runtime to run on the V8 inside Chrome.