wrote the solution for first problem

problems/waterfall/problem.txt

@@ -57,8 +57,8 @@ property then it does another GET request.
           });
 
         }).on('error'), function(e) {
-            cb(err);
-          });
+          cb(err);
+        });
       }
     ], function(err, result){
       if (err) return console.error(err);

problems/waterfall/setup.js

@@ -1,30 +1,16 @@
 var http  = require('http');
 
-function server (i, delay, port) {
-  return http.createServer(function (req, res) {
-    writeWords(i, delay, res)
-  }).listen(port)
-}
-
 module.exports = function () {
-  var servers = [
-      server(0, 100, 9345)
-    , server(1, 0,   9346)
-    , server(2, 50,  9347)
-  ]
+  var server = http.createServer(function (req, res) {
+      res.end('boom!')
+  }).listen(9345)
 
   return {
       args  : [
-          'http://localhost:9345'
-        , 'http://localhost:9346'
-        , 'http://localhost:9347'
+        __dirname + '/url.txt'
       ]
     , stdin : null
     , long  : true
-    , close : function () {
-        servers.forEach(function (server) {
-          server.close()
-        })
-      }
+    , close : server.close.bind(server)
   }
 }

problems/waterfall/solution.js

@@ -0,0 +1,30 @@
+var fs = require('fs')
+  , http = require('http')
+  , async = require('async');
+
+async.waterfall([
+  function(done){
+    fs.readFile(process.argv[2], function(err, data){
+      if (err) return done(err);
+      done(null, data)
+    });
+  },
+
+  function(data, done){
+    var body = '';
+    http.get(data.toString().trimRight(), function(res){
+      res.on('data', function(chunk){
+        body += chunk.toString();
+      });
+
+      res.on('end', function(chunk){
+        done(null, body);
+      });
+    }).on('error', function(e){
+      done(e);
+    });
+  }
+], function(err, result){
+  if (err) return console.error(err);
+  console.log(result);
+});

problems/waterfall/url.txt

@@ -0,0 +1 @@
+http://localhost:9345