One word - Javascript
Code
<SCRIPT language=Javascript>< !--
var now = new Date();
var days = new Array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday');
var months = new Array('January','February','March','April','May','June','July','August','September','October','November','December');
var date = ((now.getDate()<10) ? "0" : "")+ now.getDate();
function y2k(number){return (number < 1000) ? number + 1900 : number;}
mod = "<font face="Verdana,Arial" size="1">"
mod +=  days[now.getDay()] + ", " + months[now.getMonth()] + " " 
mod += date  +  ", " + (y2k(now.getYear())) 
document.write(mod)
document.write("</font>")
//--></SCRIPT>