I'm not even joking.

grunt-wat.js

// This was what I got, pasted into an email.
module.exports = function(grunt) {

              //Grunt Globals
              var ConcatOutputFileNameAndLocation="c:\\TestOutput.js";
              var JavascriptDirectory = 'C:\\Work\\Patch29\\StaticContent\\RootAssets\\JsLib'
              var MessageTaskStart = "StartingTask_";
              var MessageTaskEnd = "EndingTask_";
              var MessageTaskERR = "Error_";
              var MessageTaskReturnObjectValue = "ReturnObjectValue_";
              var arryOfFiles = new Array();
              var stringOfFiles;
              //Grunt Functions
              function readFiles()
              {
                                                              var tmparry = new Array();
                                                              console.log(MessageTaskStart + 'readFiles()');
                                                              var fs = require('fs');
                                                              tmparry = fs.readdirSync(JavascriptDirectory).filter(function(file) { return file.substr(-3) == '.js'});
                                                              tmparry.forEach(function(item)
                                                              {
                                                                              arryOfFiles.push("'" + JavascriptDirectory + item + "'");
                                                              });
                                                              console.log(MessageTaskEnd + 'readFiles()');
                                                              //console.log(MessageTaskReturnObjectValue + arryOfFiles);
                                                              //console.log(arryOfFiles.toString());
                                                              stringOfFiles = arryOfFiles.toString();
                                                              return true;
              }
//Grunt Tasks
              grunt.registerInitTask('ReadFiles','Read Files',function() {var done = this.async(); done(readFiles()); });
//Grunt Commands
                grunt.task.run('ReadFiles');
                grunt.registerTask('ReadFiles','ReadFiles',readFiles());
                grunt.registerTask('default', 'concat');

//Grunt Init
                grunt.initConfig(
                  {

                                              concat: {
                                              dist: {

                                                                              src: [stringOfFiles],
                                                                              dest:ConcatOutputFileNameAndLocation
                                                                }
                                                              }
                  });





};

grunt.js

// This is probably how it should've been done.
module.exports = function(grunt) {
  // Grunt Init
  grunt.initConfig({
    concat: {
      dist: {
        src: ['StaticContent/RootAssets/JsLib/**/*.js'],
        dest: 'TestOutput.js'
      }
    }
  });

  // Grunt Tasks
  grunt.registerTask('default', 'concat');
};

I love seeing new Array() in JavaScript it reminds me of Java :)

lol. Someone has not heard of globbing or read the docs.