HSL color rotation demo with canvas. Demo at: http://jsfiddle.net/mostlygeek/sM7DR/32/

hsl-canvas-test.js

(function() {
    var lastTime = 0;
    var vendors = ['ms', 'moz', 'webkit', 'o'];
    for (var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
        window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame'];
        window.cancelAnimationFrame =
        window[vendors[x] + 'CancelAnimationFrame'] || window[vendors[x] + 'CancelRequestAnimationFrame'];
    }

    if (!window.requestAnimationFrame) window.requestAnimationFrame = function(callback, element) {
        var currTime = new Date().getTime();
        var timeToCall = Math.max(0, 16 - (currTime - lastTime));
        var id = window.setTimeout(function() {
            callback(currTime + timeToCall);
        }, timeToCall);
        lastTime = currTime + timeToCall;
        return id;
    };

    if (!window.cancelAnimationFrame) window.cancelAnimationFrame = function(id) {
        clearTimeout(id);
    };
}());

(function() {
    var canvas = document.getElementById("myCanvas"),
        ct = canvas.getContext("2d");

    canvas.width = 200;
    canvas.height = 200;

    var period = 2 * Math.PI / 1000;  // convert to seconds, PI = 2/second, 2PI = 1/second...
    function drawLine(time, ct, offset, hue) {
        // luminosity of 30% +/- 10%
        var lum = Math.floor(30 + 10 * Math.sin(time * period));

        ct.beginPath();
        ct.strokeStyle = 'hsl(' + hue + ',100%,' + lum + '%)';
        ct.lineWidth = 5
        ct.moveTo(0 + offset, 0);
        ct.lineTo(50 + offset, 200);
        ct.lineTo(100 + offset, 0);
        ct.lineTo(150 + offset, 200);
        ct.lineTo(200 + offset, 0);
        ct.lineTo(250 + offset, 200);

        ct.stroke();
    }

    function draw(time) {
        ct.clearRect(0, 0, 200, 200)
        drawLine(time, ct, -50, 0);
        drawLine(time, ct, -40, 60);
        drawLine(time, ct, -30, 120);
        drawLine(time, ct, -20, 180);
        drawLine(time, ct, -10, 240);
        drawLine(time, ct,   0, 300);

        requestAnimationFrame(draw);
    }

    requestAnimationFrame(draw);
})();​