readable streams are fun.

fake-readable.js

var Readable = require('stream').Readable
  , util = require('util')
;

util.inherits(FakeReadable, Readable);
function FakeReadable(options) {
  var self = this;
  Readable.call(self);
  self.push(new Buffer('data'));
  setTimeout(function() {
    self.push(new Buffer('moar data!'));
    self.push(null);
  }, 2000);
}
FakeReadable.prototype._read = function(size) {
  process.stdout.write('\nreadable!\n');
};

new FakeReadable()
  .pipe(process.stdout)
;