var cheatCode = [38,38,40,40,37,39,37,39,66,65]; // Konami Cheat Code

Rx.Observable
    .fromEvent(document, 'keydown')
    .map(function(x) { return x.keyCode; })
    .windowWithCount(cheatCode.length, 1)
    .flatMap(function(xs) { return xs.toArray(); })
    .do(function (x) { console.log(x); })
    .filter(function(xs) { return _.isEqual(cheatCode, xs); })
    .subscribe(function(x) { console.log('CHEATER!!11elf'); });