Just a short note on discovery (which is not too much of a discovery actually): you can use pre- & post- hooks in npm-scripts for your own custom tasks. So, next time you would need to run several things as part of one task, you could leverage those.

  "scripts": {
    "premyscript": "echo \"Pre stuff\"",
    "myscript": "echo \"LOL MY SCRIPT\" ",
    "postmyscript":"echo \"Post stuff\""

So, if we run npm run myscript in the folder where package.json would hold abovementioned lines, we would see something like:

$ npm run myscript

> npm-test@0.0.0 premyscript /home/sudodoki/Projects/npm-test
> echo "Pre stuff"

Pre stuff

> npm-test@0.0.0 myscript /home/sudodoki/Projects/npm-test
> echo "LOL MY SCRIPT"


> npm-test@0.0.0 postmyscript /home/sudodoki/Projects/npm-test
> echo "Post stuff"

Post stuff

UPD (21/7/14): Note on this became part of oficial documentation. OSS FTW