Require in runInNewContext

demo.js

var Module = require('module');
var vm = require('vm');
var path = require('path');

var filename = process.cwd() + '/lib/eval.js';
var mod = new Module(filename);

var context = {
    module: mod,
    __filename: filename,
    __dirname: path.dirname(filename),
    require: function (path) {
        return mod.require(path);
    }
};
console.log(context);

var code = require('fs').readFileSync(filename).toString();

var m = vm.createScript(code.toString('utf8'), filename);
m.runInNewContext(context);

eval.js

// put this file inside ./lib directory
require('./includeme');

includeme.js

// put this file inside ./lib directory
console.log('included');

log

~: ) NODE_DEBUG=module node demo
looking for "/Users/anatoliy/projects/sandbox/demo" in ["/usr/local/lib/node_modules","/Users/anatoliy/.node_modules","/Users/anatoliy/.node_libraries","/usr/local/Cellar/node/0.6.0/lib/node"]
load "/Users/anatoliy/projects/sandbox/demo.js" for module "."
Module._load REQUEST  module parent: .
load native module module
Module._load REQUEST  vm parent: .
load native module vm
Module._load REQUEST  path parent: .
load native module path
{ module: 
   { id: '/Users/anatoliy/projects/sandbox/lib/eval.js',
     exports: {},
     parent: undefined,
     filename: null,
     loaded: false,
     exited: false,
     children: [] },
  __filename: '/Users/anatoliy/projects/sandbox/lib/eval.js',
  __dirname: '/Users/anatoliy/projects/sandbox/lib',
  require: [Function] }
Module._load REQUEST  fs parent: .
load native module fs
Module._load REQUEST  ./includeme parent: /Users/anatoliy/projects/sandbox/lib/eval.js
looking for "./includeme" in ["/Users/anatoliy/projects/sandbox/node_modules","/Users/anatoliy/projects/node_modules","/Users/anatoliy/node_modules","/Users/node_modules","/node_modules",".","/usr/local/lib/node_modules","/Users/anatoliy/.node_modules","/Users/anatoliy/.node_libraries","/usr/local/Cellar/node/0.6.0/lib/node"]

node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
Error: Cannot find module './includeme'
    at Function._resolveFilename (module.js:334:11)
    at Function._load (module.js:279:25)
    at Module.require (module.js:357:17)
    at /Users/anatoliy/projects/sandbox/run.js:13:20
    at /Users/anatoliy/projects/sandbox/lib/eval.js:1:1
    at Object.<anonymous> (/Users/anatoliy/projects/sandbox/run.js:21:3)
    at Module._compile (module.js:432:26)
    at Object..js (module.js:450:10)
    at Module.load (module.js:351:31)
    at Function._load (module.js:310:12)

A solution without vm (see nodejs/node-v0.x-archive#2525)

// replacement for demo.js
var path = require('path');
var filename = path.join(process.cwd(), '/lib/eval.js');
var code = require('fs').readFileSync(filename).toString();

requireCode(code, filename);


function requireCode(code, pathToCode) {
    var vm = require("vm");
    var path = require("path");
    var Module = require("module").Module;

    var filepath = path.resolve(process.cwd(), pathToCode);
    var filename = path.basename(filepath);
    var dirname = path.dirname(filepath);

    var cachedModule = Module._cache[filepath];
    if (cachedModule) {
        return cachedModule.exports;
    }

    var mod = new Module(filepath, module);
    Module._cache[filepath] = mod;

    mod.filename = filepath;
    mod.paths = Module._nodeModulePaths(dirname);

    mod._compile(code, filepath);
    mod.loaded = true;

    return mod.exports;
}

https://github.com/WolfgangKluge/node-helpers