While today would be the 17th Sunday after Pentecost, every seven years or so the 15th of September falls on Sunday, as it does today, and we commemorate the Seven Sorrows of our Blessed Lady. In fact, up until the calendar reform under Pope Saint Pius X, the feast was fixed on the third Sunday of September. The feast has been celebrated throughout the Western Church since Pope Pius VII returned from exile under Napoleon.
But devotion to the Seven Sorrows goes back before the Church assigned a special Mass and feast day. Some of the Sorrows were already being meditated upon in the Rosary, but in the thirteenth century the order known as the "Servants of Mary" or simply the "Servites" was founded with the expressed purpose of sanctifying its members, and those with whom they came in contact, through meditation on the sorrows of our Blessed Mother standing at the foot of the Cross. Over the centuries there have been different lists of the Sorrows of Mary, at first only those surrounding the Crucifixion, but later including earlier events as well. They are usually seven in number, and today the list is more or less fixed to include the following:
The Servite practice is to meditate on each of these sorrows, much like one meditates on the Rosary. The chaplet begins with the Act of Contrition, for the primary purpose of this devotion is to call to mind that it is our sins that caused the suffering of Jesus, and consequently of His Mother, each sorrow is announced like the mysteries of the Rosary, followed by the "Our Father" and seven "Hail Mary's. There is abundant material for meditation on the Sorrows -- the Bible is the best place to start, of course. But you may also find some useful considerations in books that deal with the Rosary and the Stations of the Cross -- for obviously all three of these devotions overlap somewhat.
But aside from being familiar with each of these events, probably the most effective way to meditate on the sorrows is to try to put one's self in the place of the Blessed Mother. Try to imagine what it must have been like to hear the prophecy of Simeon, or the panic she must have felt when soldiers were systematically murdering all of the little boys in and around Bethlehem. Try to imagine the intense sorrow that a mother would feel on meeting her son on the way to his execution, or on seeing him die the hideous death of crucifixion, and, perhaps worst of all, the unspeakable loneliness that she must have felt on that first Holy Saturday.
Sometimes we lose sight of the ugliness and the consequences of sin. It is easy to develop the mindset that "it doesn't matter, as long as I am not hurting anybody." We live in a world that supports behavior with no reference to Almighty God. So, pretty regularly, we ought to make an examination of our conscience. And to reinforce our resolve to do better in the future we ought to spend some time in making the Stations of the Cross, or saying the Rosary, or meditating on the Seven Sorrows of our Blessed Mother.
Information taken from the http://www.members.tripod.com/~maryimmaculate/dolours.html site is gratefully acknowledged.