The Big Three
Jews talk about the Big Three during this season: 1) tzedeka, meaning charity; 2) tefilla, meaning prayer; and 3) teshuva, which literally means return, but really suggests change, repentance, improvement. According to tradition, God passes judgment on Jews during this time, deciding who will live for another year, who will be inscribed in the Book of Life. According to the same tradition, partaking in these activities can help ensure a favorable fate for the coming year. Even if you don't believe in such a literal God, you will likely be uplifted spiritually by these righteous pursuits.