In the Dominican Rite (and in other medieval rites as well, I am sure) the season of Epiphanytide includes the wonderful Magnificat antiphon Peccata mea, Domine..., which is prayed at 1st Vespers of the Sundays after the Epiphany, up to and including Septuagesima Sunday.
I don't know anything about it's origin, but it is a brief and beautiful summary of the absolute necessity of humility and repentance for any healthy interior life. I look forward to praying it each year.