Apparently, there are two St. Patrick's Days this year. There is a new one on the 15th (declared by the Pope- seriously), and then the traditional one on the 17th. You can start off even earlier this year–the 14th at Kells.
Don't forget about the Shamrock run/stride/stumble as well. Official site here. Below is a pic of the SE Shamrockers of 2003.