In Roman Catholicism, Holy Days of Obligation are the other days in addition to Sundays that Catholics are obligated to attend Mass. Below are the Holy Days of Obligation and Liturgical celebrations for the year 2009:
Holy Days:
Sat., August 15, 2009 Solemnity of the Assumption of the Blessed Virgin Mary (abrogated because it falls on a Saturday)
Sun., November 1, 2009 Solemnity of All Saints
Tues., December 8, 2009 Immaculate Conception of the Blessed Virgin Mary
Friday, December 25, 2009 The Nativity of the Lord (Christmas)
Liturgical Celebrations:
February 25, 2009 Ash Wednesday
April 5, 2009 Palm Sunday
April 9, 2009 - Holy Thursday
April 10, 2009 Good Friday
April 11, 2009 Holy Saturday: **The Easter Vigil**
April 12, 2009 Easter Sunday
April 19, 2009 Divine Mercy Sunday
May 21, 2009; transferred to Sun. May 24, 2009 The Ascension of the Lord (Solemnity Observed)
May 31, 2009 Pentecost Sunday (Solemnity Observed)
June 7, 2009 Trinity Sunday
Thurs. June 11, 2009; transferred to Sunday June 14, 2009) Corpus Christi
November 22, 2009 Our Lord Jesus Christ the King (Last Sunday of the liturgical year)
November 29, 2009 First Sunday of Advent (Beginning of new liturgical year)