client.js

var express = require('express')
  , app = express.createApplication();

app.get('/', function(req){
  req.render('index').replace('#content');
});

app.get('/list', function(req){
  req.render('todo/list', { items: items })
     .replace('#content');
});

app.on('add-item', function(item){
  app.render('todo/item', { item: item })
    .appendTo('#items');
});

server.js

var app = express.createServer();

app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.bodyParser());

var items = [];

app.get('/', function(req, res, next){
  res.render('index');
});

app.get('/list', function(req, res, next){
  res.render('todo/list', { items: items });
});

app.post('/item', function(req, res, next){
  items.push(req.body);
  if (req.xhr) return res.send(req.body);
  res.redirect('back');
});

app.listen(3000);