SuperDoc makes a nice local website to help you look at the npm packages you use. It currently can render their markdown docs. One day it will show api documentation and automatically docco-ify them.
Since we're not yet in npm, do this for now to get started:
git clone https://github.com/mullr/SuperDoc
cd SuperDoc
npm install
npm link
Then go to some directory in your project which uses npm and type superdoc.
SuperDoc was developed on OSX and may work on other platforms as well.