... and I don't "hate" those pages. I love the concept, it's the execution that could use some help... and as we discussed, I'd probably not use SVG for that, or if I did I'd find a way to make it a bit more... responsive. Controlling it is very awkward and slow.
Like your Hue and Lightness sections I'd have a linear-gradient instead of the boxes, and trap the mouse position on mouse-down in realtime with mousemove instead of single-fire clicks. Same for the rotating box where I'd use arctan2 to translate the mouse position into an angle.
But then, I'm the nutter who uses arctangents to do 3d projection instead of sin/cos and/or matrixes. Explain to me again how 64 multiplies of three sin and three cos is 'faster' than two arctangents? NOT that I'm saying the entire world of 3d computer graphics is doing it wrong... not at all.