var router = new Router();

// Simple single-function
router.on('/some/path', function () {
  // Do something...
});

// Params in single-function
router.on('/some/path/:thing', function (thing) {
  // Do something with 'thing'...
});

// Full Object: before, load and unload events
router.on('/some/path/:thing', {
  // Check before loading
  before: function (fn) {
    if (loggedIn) {
      // Pass through...
      fn(true);
    } else {
      // You shall not pass
      fn(false);
    }
  },
  // Run on load
  load: function (thing) {
    // Print variable from params
    console.log(thing);
  },
  // Run on leave
  unload: function () {
    console.log('Outta Here!');
  }
});

// Handling 404's
router.on('/404', function () {
  // Print 'page not found' or something...
  // Current (pre-nav) page still appears as URL
})