The jokes on Singh's page are pretty lame. There's a selection of mathematical jokes at <a href="http://mathoverflow.net/questions/1083/do-good-math-jokes-exist" rel="nofollow">http://mathoverflow.net/questions/1083/do-good-math-jokes-ex...</a> (I <i>thought</i> I originally saw that link on HN but may be misremembering), of which the cleverest are very much cleverer (and to my mind funnier) than those. However, they're mostly submitted by, and rated by, actual mathematicians, so many presuppose quite a lot of mathematical knowledge.