Faith Street has a great primer with everything you ever wanted to know about the origin and practice of Lent.
Did you know, for example, that in the early days of the Christian Church, Lent "was a two-day fast beginning on Good Friday and intended for those preparing for baptism." In addition, you had to avoid dairy products and eggs. All that, of course, changed over time, according to Carrie Mitchell, the graduate intern at Faith Street who wrote the essay.
Mitchell notes that many in the Protestant faith spoke out against Lent. John Calvin called it a "superstitious observance," and "Ulrich Zwingli, a Swiss reformer, led one of the initial protests against Lenten traditions in 1522, arguing that its rules were centered on obeying Rome rather than the gospel."
The pillars of Lent, Mitchell says, are fasting, praying, and almsgiving. She says that "for all Christians who observe it, Lent is intended to deepen one’s appreciation of Jesus’ suffering and sacrifice. It’s a period of penitence in preparation for the celebration of Easter."