Via Keith comes this online course on learning Prolog.
Why do I mention this? Well, I remember Prolog. I remember defining white, red, and blue houses, and who ate fish in one, and meat in another. I remember turning my head inside out trying to figure out what the hell was happening! Never again I tell you! *shudder*
But, turning your head inside out is -Fun-.. watch the pretty lights as monkey pushes window to the box, puts box on head, window on box, and takes banana, and slips in it, and falls down, and die..