In the traditional Roman Catholic calendar (the calendar still used in the Extraordinary Form of the Mass, also known as the Traditional Latin Mass), the three Sundays before Lent were a special pre-Lenten period--"the front porch of Lent," as our parish priest likes to say. Those Sundays were called Septuagesima Sunday, Sexagesima Sunday, and Quinquagesima Sunday--from the Latin words meaning 70, 60, and 50, roughly the number of days each falls before Easter Sunday.
But the Latin Rite Church, in both the old (pre-1970) and new liturgical calendars, has nothing on the Eastern Church, both Catholic and Orthodox. For Eastern Christians who calculate Easter according to the Gregorian calendar, the preparation for Lent begins four Sundays before Western Ash Wednesday. (Eastern Christians don't celebrate Ash Wednesday as the first day of Lent; instead, they begin Lent on Clean Monday, two days before Ash Wednesday.)
The fourth Sunday before Clean Monday is the Sunday of the Publican and Pharisee, and on that day, the Parable of the Publican and the Pharisee (Luke 18:10-14) is read, to turn the thoughts of the congregation to repentance. The next Sunday is the Sunday of the Prodigal Son, and the Parable of the Prodigal Son (Luke 15:11-32) reminds us that it's never too late to repent of our sins and to return to our Father.
After the Sunday of the Prodigal Son comes Meatfare Sunday, which (for those Eastern Christians on the Gregorian calendar) in 2013 falls on February 3. The Eastern Christian discipline for the Lenten fast was historically much stricter than the rules for fasting in the Western Church, and Meatfare Sunday was the last day on which Eastern Christians could eat any meat. The following Sunday, Cheesefare Sunday, is the last day on which Eastern Christians can eat any dairy products. (Cheesefare Sunday is also known as Forgiveness Sunday, because at the end of Divine Liturgy that day, the faithful ask one another for forgiveness, in order to enter Lent with a clean conscience and as a true Christian community.)
Over the years, many Eastern Catholics and Eastern Orthodox relaxed the fasting rules for Lent, but in recent years, quite a few have returned to the traditional discipline, which forbids the use of eggs as well as meat and dairy products. It's a rigorous regimen, but one which Eastern Christians who practice it say bears great spiritual fruit. And it's something to keep in mind the next time we Western Catholics think that our 40 days of Lent seems too long!