Lent is a season of soul-searching and repentance. It is a season for reflection and taking stock. Lent originated in the very earliest days of the Church as a preparatory time for Easter, when the faithful rededicated themselves and when converts were instructed in the faith and prepared for baptism. By observing the forty days of Lent, the individual Christian imitates Jesus’ withdrawal into the wilderness for forty days. All churches that have a continuous history extending before AD 1500 observe Lent. The ancient church that wrote, collected, canonized, and propagated the New Testament also observed Lent, believing it to be a commandment from the apostles. (See The Apostolic Constitutions, Book V, Section III.)
"The intention [of Lent] was to imitate Jesus who after his baptism in the Jordan fasted for forty days (Mt 4.2; Lk 4.1-2). The Church Fathers also saw in the practice an echo of the forty days Moses fasted on Sinai (Ex 34.28) and the forty days Elijah fasted on his journey to Mount Horeb (1 Kings 19.8), as well as of he forty years of Israel's sojourn in the wilderness" The Liturgical Year, Adolf Adam
"Dear brothers and sisters, Lent culminates in the Paschal Triduum, in which this year, too, we shall celebrate divine justice – the fullness of charity, gift, salvation. May this penitential season be for every Christian a time of authentic conversion and intense knowledge of the mystery of Christ, who came to fulfill every justice." Pope Benedict XVI's message for Lent 2010
40 ways to get the most out of Lent by Dr. Marcellino D’Ambrosio
Catholic Encyclopedia entry for Lent
A Guide to the Rules for Lent
Address for Lent 2015 by Pope Francis
40 Ideas for Lent by Rachel Evans
Catholic Culture's Lent Page - Includes a workshop on the meaning of Lent, with message from the Pope, regulations, and various questions answered.
USCCB (United States Conference of Catholic Bishops) Lenten website - covers topics such as what we believe, what we celebrate, how we live, and how we pray.
St Anthony Messenger Press Lent website - Includes daily reflections and readings, as well as answers to questions about Lent.
The Vatican Lenten website - Includes Pope Benedict's Lent message, Lent Music, and various other recordings.
Catholic Online's Lent/Easter website - Various resources including a topical look at Lent, covering things from prayer, fasting, scrutinies and palms.
Relfections and Suggestions - The Catholic Thing
Creighton University's Praying Lent page - Many, many prayers, reflections, guides, and even recipes for making Lent a more meaningful experience.
Creighton University's Daily Reflections
Our Catholic Faith
Based on the writings of St. Francis de Sales
Written by Francis Xavier Lasance
Written by John Henry Cardinal Newman (some in latin)