It's not an exam! The Daily Examen is a technique of prayerful reflection on the events of the day in order to detect God’s presence and discern his direction for us. It is particularly associated with St Ignatius of Loyola and there are many variations of it. The basic strategy is to become aware of God’s presence, review the day with gratitude; pay attention to your emotions; choose one feature of the day and pray from it; look toward tomorrow.
Christians are really encouraged to build this practice into their night prayer. Sometimes we need a little help to stay focused throughout the day too though!