First appearance to the children at Fatima. It's a great day to pray the rosary, especially since it's a Wed and therefore a Glorious Mystery day.
If you are not familiar with the Fatima apparitions, you can read more here:
https://www.ewtn.com/fatima/our-lady.asp.
If you have not prayed the rosary in a while, this site is a great aid:
https://www.scripturalrosary.org/BeginningPrayers.html.
I used to consider Marian devotions the "weird uncle" of Catholicism, not quite idolatrous, but also not necessary. Lately, however, I have come to appreciate Mary both as aspirational example of the Christian ideal and as a powerful intercessor. My commitment to a daily rosary has deepened and enriched my prayer/spiritual life, increased my ability to resist temptations, and grown my ability to just "say yes" to God.