The Jewish books of ethics are replete with the notion that any available moment that a Jew has he should be engaged in the study of Torah - and every moment available that is not utilized for the study of Torah is most likely used for idle matters which in turn leads to sins such as hurtful speech nor slander (paraphrased from Torat Habayit from the Chafetz Chaim).
Having said that is there any room in Judaism for an observant Jew to engage in personal hobbies, take trips to other countries, read secular literature or the like? If so are there any guidelines or Halachot for how and when on may engage in these activities?