Named days

Easter Sunday is the most important day in the Christian calendar.
Low Sunday, first Sunday after Easter, is also known as the Octave of Easter, White Sunday, Quasimodo Sunday, Alb Sunday, Antipascha Sunday, and Divine Mercy Sunday.
Palm Sunday is the Sunday before Easter.
Passion Sunday, formerly denoting the fifth Sunday of Lent; since 1970 the term applies to the following Sunday also known as Palm Sunday.
Septuagesima, Sexagesima and Quinquagesima Sunday are the last three Sundays before Lent. Quinquagesima ("fiftieth"), is the fiftieth day before Easter, reckoning inclusively; but Sexagesima is not the sixtieth day and Septuagesima is not the seventieth but is the sixty-fourth day prior. The use of these terms was abandoned by the Catholic church in the 1970 calendar reforms (the Sundays before Lent are now simply "Sundays in ordinary time" with no special status). However, their use is still continued in Lutheran tradition: for example, "Septuagesimae".
Stir-up Sunday is the last Sunday before Advent.
Whitsunday "White Sunday" is the day of Pentecost.
Trinity Sunday is the first Sunday after Pentecost.
Gaudete Sunday is the third Sunday of Advent.
Laetare Sunday is the fourth Sunday of Lent.
Good Shepherd Sunday is the fourth Sunday of Easter.
Super Bowl Sunday
Bloody Sunday
Selection Sunday