Yesterday was the Solemnity of the Most Holy Trinity, our school's patronal feast day. Trinity Sunday always falls on the Sunday after Pentecost so it comes at a crazy time of a year for our school (or depending on when Easter is, when we're already out of school). Thus, we've never able to mark the feast well. Someday I'd like to see if we can find a way to celebrate this great feast.
There are many prayers to the Trinity but my favorite comes from St. Patrick's long prayer called the Lorica of St. Patrick. This excerpt was our prayer for this morning:
I arise today Through a mighty strength, the invocation of the Trinity, Through belief in the Threeness, Through confession of the Oneness of the Creator of creation.