Especially to those of you with some Welsh blood in you!
St. David's is not as well known as St. Patrick's. I think this is because the Welsh tend to spend it going to a church to sing with others, while our Celtic cousins tend to spend it going to a bar and drinking and singing with other intoxicated people.
To celebrate, turn your speakers on and listen to this rendition of "Land of My Fathers". AKA "Mae Hen Wlad Fy Nhadau", the Welsh national anthem. It is a truly stirring song that I learned from my grandmother while still a child. She was born in Wales, came here as a young child, but lived in a home where Welsh was the first language.
Note the spelling in the sub-titles as you listen. Welsh people clearly have to be very smart or they never can read the road signs.