Minimalist Hex Clock
HTML/CSS/JavaScript 207 183 180 161 152
Tested and working in the latest Firefox and Chrome browsers.
<body id=b onload=setInterval("b.innerHTML=b.bgColor=Date().replace(/.*(..):(..):(..).*/,'#$1$2$3')",0) text=#fff style=position:fixed;top:50%;left:47%>
Demo Here