Something like this:
var now = new Date(); var currentDate = now.getHours();
var hour_var = new Array(
"http://www.your-domain.com/url-1",
"http://www.your-domain.com/url-2",
"http://www.your-domain.com/url-3",
"http://www.your-domain.com/url-4",
"http://www.your-domain.com/url-5",
"http://www.your-domain.com/url-6",
"http://www.your-domain.com/url-7",
"http://www.your-domain.com/url-8",
"http://www.your-domain.com/url-9",
"http://www.your-domain.com/url-10",
"http://www.your-domain.com/url-11",
"http://www.your-domain.com/url-12",
"http://www.your-domain.com/url-13",
"http://www.your-domain.com/url-14",
"http://www.your-domain.com/url-15",
"http://www.your-domain.com/url-16",
"http://www.your-domain.com/url-17",
"http://www.your-domain.com/url-18",
"http://www.your-domain.com/url-19",
"http://www.your-domain.com/url-20",
"http://www.your-domain.com/url-21",
"http://www.your-domain.com/url-22",
"http://www.your-domain.com/url-23",
"http://www.your-domain.com/url-24");
document.write('<a href="' + hour_var[currentDate] + '">click here for featured model of the hour</a>');