Where I live in the Midwest of the United States of America, the Irish are celebrating the "Wearing of the Green". Many of them aren't Irish but they act like it until they've had their fill of booze or beer and go to sleep.
St. Patrick's Day in Ireland is a religious holiday and celebrated by predominantly Roman Catholic families. In the United States people put on drink and use it as an excuse to get drunk.
Regardless of how you celebrate...Happy Saint Patrick's Day!