As you know, Trinity Sunday has recently passed. Matt led a good discussion of the history and meaning of the Christian teaching on the Trinitarian god, as well as some of its implications (and applications) for our lives here and now. I recommend giving it a listen; the podcast can be found over at his blog.
See also To the Quiet: "The Holy Trinity and Icons."
And if you think this was late, I still have links for Corpus Christi...