This Sunday is Laetare Sunday, so called from the first words of the Introit at Mass, "Laetare Jerusalem" - "Rejoice, O Jerusalem". According to the Catholic Encyclopedia:
Strictly speaking, the Thursday before Laetare Sunday is the middle day of Lent, and it was at one time observed as such, but afterwards the special signs of joy permitted on this day, intended to encourage the faithful in their course through the season of penance, were transferred to the Sunday following. They consist of (like those of Gaudete Sunday in Advent) in the use of flowers on the altar, and of the organ at Mass and Vespers; rose-coloured vestments also allowed instead of purple [...] The contrast between Laetare and the other Sundays is thus emphasized, and is emblematical of the joys of this life, restrained rejoicing mingled with a certain amount of sadness.
We've been looking the last few Fridays at the Sorrowful Mysteries of the Rosary, but I thought this an occasion to lighten up a bit. (That plus the fact that there are only five Sorrowful Mysteries and seven Fridays in Lent!) So when you see the rose vestments and the flowers and hear the music on Sunday, allow your sprits to lighten. Have you had trouble with your resolutions or sacrifices during Lent? Don't let it be an occasion of despair; there's still time. As we heard recently in the parable of the workers, even the worker who only works an hour will get his just wage. Redouble your efforts; pray to Our Lord and Our Lady for the strength to make your commitment, offer your sacrifices knowing that He will do great things with them.