beware -- oh, never mind

There was a time when March 15th would roll around and it was fun to say, "Beware the Ides of March!", and most people would know what you're referring to.  That was back when most had been required to read Shakespeare in English class.  Now I could explain that the Ides of March is when Julius Caesar met his Waterloo -- but that would, first of all, bring in two unrelated historical moments -- and many would say "Julius who?"