heh, just ask them, "how in your right mind can you believe that you can calculate the return of jesus through daniel 4?"
http://members.aol.com/gparrishjr/d4.html
i found that link interesting, but i don't know how true it is because i only browsed over it. but, the big point is that if we could actually calculate the return of jesus thru an equation, then we should be able to gain answer any other technological question for anything else in the world........