Breach is a nodejs browser built with js from the ground up.
Sitting niceley on node and chromium it acts as perfectly useable browser. Where it becomes interesting is the fact that it can be extended with ease just like modern browsers (e.g. firefox and chrome). With extentions though it could mean that you could make the browser itself into a server, this is very powerful for distributed systems.
Bad point though is that its not available on windows yet. No idea why as windows runs both node and chromium but they must be having some difficulties.