An easter egg which will turn your page and your head ! (jQuery is needed)

knm.js

(function ($) {
    var kkeys = [];
    var knm = ['38', '38', '40', '40', '37', '39', '37', '39', '66', '65'];
    var knmTransitionClass = 'knm-transition';
    var $html = $('html');

    var transitionEnd = null;
    var el = document.createElement('div');
    var transEndEventNames = {
        WebkitTransition : 'webkitTransitionEnd',
        MozTransition    : 'transitionend',
        OTransition      : 'oTransitionEnd otransitionend',
        transition       : 'transitionend'
    };

    for (var name in transEndEventNames) {
        if (el.style[name] !== undefined) {
            transitionEnd = transEndEventNames[name];
        }
    }

    // browser do not support transition
    if (transitionEnd === null) {
        return;
    }
    
    $('head').append([
        '<style>',
        '  /* konami fun */',
        '  .knm-transition {',
        '    -moz-transition: all 5000ms ease-in-out;',
        '    -o-transition: all 5000ms ease-in-out;',
        '    -webkit-transition: all 5000ms ease-in-out;',
        '    -webkit-transition: all 5000ms ease-in-out;',
        '    transition: all 5000ms ease-in-out;',
        '  }',
        '</style>'
    ].join(''));

    function nextRotation(currentRotation) {
        if (currentRotation === null) {
            return 45;
        }

        var arr = currentRotation.split('-');
        var degree = parseInt(arr[1], 10) + 45;
        return degree === 360 ? 45 : degree;
    }

    $(window).on('keydown', function (e) {
        kkeys.push(e.keyCode);
        if (kkeys.toString() === knm.toString()) {
            var currentRotation = null;
            var currentClasses = $.makeArray($html[0].classList);
            for (var i = 0; i < currentClasses.length; i++) {
                if (currentClasses[i].indexOf('knm-') !== -1 && currentClasses[i] !== knmTransitionClass) {
                    currentRotation = currentClasses[i];
                    $html.removeClass(currentClasses[i]);
                    break;
                }
            }

            $html.one(transitionEnd, function () {
                $html.removeClass(knmTransitionClass);
            });
            var next = nextRotation(currentRotation);
            $html.addClass(knmTransitionClass + ' knm-' + next).css({
                '-webkit-transform': 'rotate(' + next + 'deg)',
                '-ms-transform': 'rotate(' + next + 'deg)',
                transform: 'rotate(' + next + 'deg)'
            });
            kkeys = []; // reset to continue
            return;
        }

        if (kkeys.length === knm.length) {
            kkeys = [];
        }
    });
})(jQuery);