Irish Music on St. Patrick's day is a must.
There are many great Irish songs from which to choose. Although you can't learn them all, there are some that are favorites.
Costumes are a great idea if you really want to put on a show. You can choose anything from a green hat and tie to a full blown outfit. You can see Leprechaun Joe here in costume for a St. Patty's day concert.
Room decorations are a wonderful addition to set the spirit of the party.
I have to say that this website here offers a great resource for chords and lyrics to many Irish Songs. www.ourwholeworld.com/irish_lyrics_and_chords.html