An old-school mindset actually showed me this once and asked how node is not blocking. If you say "callback hell" is a reason you don't adopt node at this point(2015) you should probably sit with in the corner with the cobol engineers. (you guys make great money and there's still demand, but who wants to work with that?)

oldSchoolJS.js

OH_SHIT_I_NEED_GLOBALS = 100001;

function iWantThis () {
    while (count < window.OH_SHIT_I_NEED_GLOBALS) {
        count = Math.random()*100000;
    }
    return "I haven't googled node yet.  How does threads happen?  So blocking, much crap."
}

iWantThis();

Works a bit differently, but same general idea in a less blocking manner

function iWillWantThis(max) {
  return new Promise(function(resolve)  {
    resolve(Math.random() * max);
  });
}

function iWantSoMany(max) {
  return Promise.all(_.map(_.range(0, max),  _.partial(iWillWantThis, max)));
}

iWantSoMany(1e6+1).then(function(soMany) {
  console.log('so many! %s random numbers! first one is %s', soMany.length, _.first(soMany));
});