Happy April Fool's Day! If you'd like to translate all the ROT13 encrypted articles on Slashdot's homepage today, just run this gist through your browser's console.

translate-slashdot-rot13

var alphabet=['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'];

var rot13 = function(letter){
  var l = letter.toLowerCase();
	
	var index = alphabet.indexOf(l);
	
	var newIndex = (index + 13) % alphabet.length;
	
	return alphabet[newIndex];
};

$('.body .p i').each(function(){
	var letters = $(this).text().split("");
	var translation = "";
	for(var i=0; i < letters.length; i++){
		if(/[a-zA-Z]/.test(letters[i])){
			translation += rot13(letters[i]);
		} else {
			translation += letters[i];
		}		
		
	}
	$(this).replaceWith(translation);
});

I just wrote something very similar, and made a bookmarklet out of it:

http://bl.ocks.org/dergachev/5285534