An idiom (also called idiomatic expression) is an expression, word, or phrase that has a figurative meaning conventionally understood by native speakers. This meaning is different from the literal meaning of the idiom's individual elements. In other words, idioms don't mean exactly what the words say. (from my English pages)
Man muss die Feste feiern, wie sie fallen is a much used German idiom which roughly translates to one has to celebrate when one has the chance. Now with the annual Oktoberfest in full swing, in Munich and everywhere in the world, this proverb might come handy when talking to German speakers. But of course we use it all year round.We should not only celebrate such events which have been planned for a long time in advance. On the contrary, we shouldn't use too many opportunities for partying. "Come on, let's have another drink! It is such a nice evening. Who knows when the opportunity will arise next!  Man muss die Feste feiern, wie sie fallen."
