totalJokes = 191;
currentDate = new Date();
currentJoke = ((Math.round((currentDate.getTime() / 3600000)-0.5) % totalJokes) + 1);

document.write("<script language=");
document.write('"JavaScript" src="http://www.joth.net/jokes/');
document.write(currentJoke);
document.write('.js"></script>');