gistfile1.js

var waiting = null;
var games = {};

io.sockets.on('connection', function(socket) {
  var id = socket.id;
  var game = games[id];

  if (game === undefined) {
    if (waiting !== null && waiting !== id) {
      game = new MyGame();
      games[id] = game;
      games[waiting] = game;
      waiting = null
    }
    else {
      waiting = id;
    }
  }

  socket.on('move', function(data) {
    game.move(data);
  });
});