gistfile1.js

function get_random_color() {
    var letters = '0123456789ABCDEF'.split('');
    var color = '#';
    for (var i = 0; i < 6; i++ ) {
        color += letters[Math.round(Math.random() * 15)];
    }
    return color;
}

function getRandomArbitary (min, max) {
    return Math.random() * (max - min) + min;
}

function a(foo, rot, z, zz, sp) {
  foo.animate({rotation: rot, x:foo.attr("x") + z, y:foo.attr("y") + zz, fill:get_random_color()}, sp, function(){b(foo, rot*-1, z*-1, zz*-1, sp)} );
}

function b(foo, rot, z, zz, sp) {
  foo.animate({rotation: rot, x:foo.attr("x") + z, y:foo.attr("y") + zz, fill:get_random_color()}, sp, function(){a(foo, rot*-1, z*-1, zz*-1, sp)} );
}

paper.rect(0, 0, 640, 480, 10).attr({fill: "black"}); 

for (var i=0; i<150; i++){
  var size = getRandomArbitary(40, 80);
  var rot = getRandomArbitary(-360, 360);
  var speed = getRandomArbitary(4000, 6000);
  var x = paper.rect(getRandomArbitary(10,630), getRandomArbitary(10,470), size, size).attr({fill: get_random_color(), stroke: "#000", "stroke-width": 5, "stroke-opacity": 1});
  a(x, rot, getRandomArbitary(-150, 150), getRandomArbitary(-150, 150), speed);
}

first attempt at a 'floating particle' display

plug into http://raphaeljs.com/playground.html and click Run