On Sunday, Catholics celebrate Divine Mercy Sunday:
"During the course of Jesus' revelations to Saint Faustina on the Divine Mercy He asked on numerous occasions that a feast day be dedicated to the Divine Mercy and that this feast be celebrated on the Sunday after Easter. The liturgical texts of that day, the 2nd Sunday of Easter, concern the institution of the Sacrament of Penance, the Tribunal of the Divine Mercy, and are thus already suited to the request of Our Lord. This Feast, which had already been granted to the nation of Poland and been celebrated within Vatican City, was granted to the Universal Church by Pope John Paul II on the occasion of the canonization of Sr. Faustina on 30 April 2000.In a decree dated 23 May 2000, the Congregation for Divine Worship and the Discipline of the Sacraments stated that "throughout the world the Second Sunday of Easter will receive the name Divine Mercy Sunday, a perennial invitation to the Christian world to face, with confidence in divine benevolence, the difficulties and trials that mankind will experience in the years to come." These papal acts represent the highest endorsement that the Church can give to a private revelation, an act of papal infallibility proclaiming the certain sanctity of the mystic, and the granting of a universal feast, as requested by Our Lord to St. Faustina."
It is a grace-filled day in which a plenary indulgence may be obtained! I also recommend the Divine Mercy Chaplet and Novena.