[algorithm] Algorithm to randomly generate an aesthetically-pleasing color palette

function fnGetRandomColour(iDarkLuma, iLightLuma) 
{       
  for (var i=0;i<20;i++)
  {
    var sColour = ('ffffff' + Math.floor(Math.random() * 0xFFFFFF).toString(16)).substr(-6);

    var rgb = parseInt(sColour, 16);   // convert rrggbb to decimal
    var r = (rgb >> 16) & 0xff;  // extract red
    var g = (rgb >>  8) & 0xff;  // extract green
    var b = (rgb >>  0) & 0xff;  // extract blue

    var iLuma = 0.2126 * r + 0.7152 * g + 0.0722 * b; // per ITU-R BT.709


    if (iLuma > iDarkLuma && iLuma < iLightLuma) return sColour;
  }
  return sColour;
} 

For pastel, pass in higher luma dark/light integers - ie fnGetRandomColour(120, 250)

Credits: all credits to http://paulirish.com/2009/random-hex-color-code-snippets/ stackoverflow.com/questions/12043187/how-to-check-if-hex-color-is-too-black