Grunt submodule

package.json

{
  "name": "grunt-my-custom-webfont",
  "version": "0.0.0",
  "dependencies": {},
  "devDependencies": {
    "grunt": "0.4.1",
    "grunt-webfont": "0.4.8",
  }
}

parent-usage.js

// Project configuration.
grunt.initConfig({
  'my-custom-webfont': {
    target1: {
      //some options
    },
  },
});

tasks-internal-task.js

// pseudo-code
// sub grunt-spawn code done in each task, rather than top-level grunt module
// advantage here compare to sub-grunt is that you can pass options through to internal tasks to override defaults, but
//  also the task defines it's own name in standard grunt task way,a nd you don't have to alias it again in the parent gruntfile
//  like subgrunt
// this results in some repeated code per 'sub' task, but this can be abstracted out again via a library
// the spawn code could be in a helper npm module pulled in by each grunt sub-task

module.exports = function(grunt) {

  'use strict';

  grunt.registerTask('my-custom-webfont', function () {

    //copied from grunt-subgrunt
    // https://github.com/tusbar/grunt-subgrunt

    var defaultTaskOptions = {
      webfont: {
        //default webfont options
      }
    }

    //using spawn does not allow config to be passed to sub-tasks?
    //var done = this.async();
    //grunt.util.spawn({
    //    cmd: path.resolve('node_modules/.bin/grunt'),
    //    args: this.data.args || [],
    //    opts: {cwd: subdir},
    //  }, function(error, result, code) {
    //    if (code === 127) {
    //      grunt.log.error('Error running sub-grunt. Did you run "npm install" in the sub-project?');
    //    } else {
    //      grunt.log.writeln('\n' + result.stdout);
    //    }
    //    done(code === 0);
    //  });
    //});

    //what about another instance of grunt?
    var subGrunt = require('node_modules/grunt/lib/grunt'),
    subGrunt.mergeConfig(defaultConfig);
    subGrunt.mergeConfig(options);
    subGrunt.task.run('custom-internal-task')


 }):
 
};

require('node_modules/grunt/lib/grunt') should work just as require('grunt')