code.js

var Fiber = require('fibers');
var Future = require('fibers/future');
var ping = require('ping');

function hostCheck(host){
	var future = new Future;

	console.log("ping");

		ping.sys.probe(host, function(alive){
			future.return(alive);
			console.log("pong");
		});

	return future.wait();
}

var a = function go(){
	hostCheck("youtube.com");
	hostCheck("youtube.com");
	hostCheck("youtube.com");
	hostCheck("youtube.com");
	hostCheck("youtube.com");
	hostCheck("youtube.com");
	hostCheck("youtube.com");
	hostCheck("youtube.com");
	hostCheck("youtube.com");
	hostCheck("youtube.com");
}.future();

a();

console output

ciwolsey@parabola:~/projects/hellonode$ node index2.js 
ping
ping
pong
ping
pong
ping
pong
ping
pong
ping
pong
ping
pong
ping
pong
ping
pong
ping
pong
pong

try this man

function hostCheck(host){

    console.log("ping");

    var future = new Future;

        ping.sys.probe(host, function(alive){
            future.return(alive);
            console.log("pong");
        });

    return future.wait();
}

should go
ping > ping > ping > ping > ping > ping > ping > ping > ping > ping
pong >pong >pong >pong >pong >pong >pong >pong >pong