This Sunday is, of course, the feast of Pentecost, and in the traditional calendar, it comes with a first class octave, as befits its status as one of the big three (with Christmas and Easter) feasts of the liturgical year.
In the Ordinary Form, alas, the Octave is no more, and its back to Ordinary Time after Sunday.
This week in the traditional Benedictine Office
Sun 19 May Pentecost Sunday, Class I with Class I Octave
Mon 20 May Whit Monday, Class I
Tues 21 May Whit Tuesday, Class I
Wed 22 May Ember Wednesday, Class I
Thur 23 May Whit Thursday, Class I
Fri 24 May Ember Friday, Class I
Sat 25 May Ember Saturday, Class I