This the ONLY place to be 
http://www.griffshouston.com/
I've been there several times for St. Patricks Day. Good times. Also, not too far away Kenneally's Irish Pub is a blast as well. When I lived in Houston another place was Birraporetti's under Sherlocks on West Gray if it's still open. One of my favortie holidays......looking forward to it in Dallas this year.
