listen to any events on socket.io / node EventEmitter; public domain own your risk

a.js

var SocketIO = require('socket.io')
  , HTTP = require('http');

var orig_emit = SocketIO.Socket.prototype.$emit // http://nodejs.org/api/events.html#events_emitter_emit_event_arg1_arg2
SocketIO.Socket.prototype.$emit = function() {
  orig_emit.apply(this, arguments)
  var args = Array.prototype.slice.call(arguments);
  var event = args.shift();
  orig_emit.apply(this, ['anything', event, args]);
};

var app = HTTP.createServer(function (request, response) {
  response.writeHead(404, {});
  response.end('');
});
app.listen(config.app);
var io = SocketIO.listen(app);

io.sockets.on('connection', function (socket) {
  socket.on('anything', function (event, args) {
    console.log("event: ", event, args);
  });
});

hack.js

(function() {
  var orig_emit = SocketIO.Socket.prototype.$emit // http://nodejs.org/api/events.html#events_emitter_emit_event_arg1_arg2
  SocketIO.Socket.prototype.$emit = function() {
    orig_emit.apply(this, arguments)
    var args = Array.prototype.slice.call(arguments);
    var event = args.shift();
    orig_emit.apply(this, ['anything', event, args]);
  }
})();