The web we see today is built on code, and all of the various colours we see are mostly written in CSS as HEX values. For example, the blue colour on this blog has a HEX value of #3FC0F6, and the grey background has a HEX value of #F1F1F1.
So, here’s an experiment that turns time into colour by taking the values of the hours, minutes and seconds and using them as HEX values: http://jamesdowen.com/projects/hextime/.