A small bit of JavaScript that recognizes the Konami code and triggers an event of your choice.
Either load konami.js through a script tag or copy and paste the method in there to some place where you want it.
Do something like this
konami(function () {
alert('ding');
});
This will register a listener on all key(up) events, wait for the right sequence and then call the supplied function, in this case show 'ding' in an alert box.