On the first of Shevat in the year 2488 from creation, Moses convened the Jewish people and began the 37-day "review of the Torah" contained in the Book of Deuteronomy, which he concluded on the day of his passing on Adar 7 of that year.
Today is Rosh Chodesh (“Head of the Month”) for the month of Shevat.
Special portions are added to the daily prayers: Hallel (Psalms 113-118) is recited -- in its "partial" form -- following the Shacharit morning prayer, and the Yaaleh V'yavo prayer is added to the Amidah and to Grace After Meals; the additional Musaf prayer is said (when Rosh Chodesh is Shabbat, special additions are made to the Shabbat Musaf). Tachnun (confession of sins) and similar prayers are omitted.
Many have the custom to mark Rosh Chodesh with a festive meal and reduced work activity. The latter custom is prevalent amongst women, who have a special affinity with Rosh Chodesh -- the month being the feminine aspect of the Jewish Calendar.
Links:
The Jewish Month of Shevat
The Laws of Rosh Chodesh
How Does a Jewish Woman Celebrate Rosh Chodesh?
Yom Kippur is described in many ways. One very poignant description is that it is “once in a year.”
You see, the human soul is also described in many ways, with five different names, each describing a deeper level of her being. The fifth, deepest level is called yechidah, which means “one and unique.” Yechidah is the soul as she is fused and one with her Creator, so that the two are an inseparable whole.
Yom Kippur is the day that the essential bond of yechidah shines within the time and space in our world.
Meaning that once in a year, the One Above unites with the essential oneness of the soul here below within each one of us.
All else falls away.