Super basic Y.App example

gistfile1.js

// Imagine that `Y.User`, `Y.UsersView`, and `Y.UserView` have been defined.
var app = new Y.App({
    views: {
        users: {
            type    : Y.UsersView,
            preserve: true
        },

        user: {
            type  : Y.UserView,
            parent: 'users'
        }
    }
});

app.route('/users/', function () {
    this.showView('users');
});

app.route('/users/:id/', function (req) {
    var user = new Y.User(req.params.id);
    user.load(function () {
        app.showView('user', {model: user});
    });
});

app.dispatch().render();