I know this for several factors. 1) Old Testament prophecies that require Christ to come during the time that He did:
Gen_49:10 The sceptre shall not depart from Judah, nor a lawgiver from between his feet, until Shiloh come; and unto him shall the gathering of the people be.
2) The general stupidity, blasphemies and superstitions of your holiest Rabbis:
"On coming from a privy a man should not have sexual intercourse till he has waited long enough to walk half a mil, because the demon of the privy is with him for that time; if he does, his children will be epileptic" (Babylonian Talmud, Gittin 70a)
On that day R. Eliezer brought forward every imaginable argument,3 but they did not accept them. Said he to them: 'If the halachah agrees with me, let this carob-tree prove it!' Thereupon the carob-tree was torn a hundred cubits out of its place — others affirm, four hundred cubits. 'No proof can be brought from a carob-tree,' they retorted. Again he said to them: 'If the halachah agrees with me, let the stream of water prove it!' Whereupon the stream of water flowed backwards — 'No proof can be brought from a stream of water,' they rejoined. Again he urged: 'If the halachah agrees with me, let the walls of the schoolhouse prove it,' whereupon the walls inclined to fall. But R. Joshua rebuked them, saying: 'When scholars are engaged in a halachic dispute, what have ye to interfere?' Hence they did not fall, in honour of R. Joshua, nor did they resume the upright, in honour of R. Eliezer; and they are still standing thus inclined. Again he said to them: 'If the halachah agrees with me, let it be proved from Heaven!' Whereupon a Heavenly Voice cried out: 'Why do ye dispute with R. Eliezer, seeing that in all matters the halachah agrees with him!' But R. Joshua arose and exclaimed: 'It is not in heaven.'4 What did he mean by this? — Said R. Jeremiah: That the Torah had already been given at Mount Sinai; we pay no attention to a Heavenly Voice, because Thou hast long since written in the Torah at Mount Sinai, After the majority must one incline." (Babylonian Talmud, Baba Mezi'a 59b)
(There are much worse things than this in the Talmud, such as Rabbis lying to Gentiles, lying to other Jews, and many other heinous teachings and acts.)
And lastly, besides the prophecies mentioned before, all these wonderful little Easter Eggs!
http://www.ldolphin.org/camp.html