Here are my favorite teams.

(All of the logos are on the banner if you didn't notice)
Leinster Rugby
    Based in Dublin, Ireland
    Competes in Magner's League and Heineken Cup
    Famous Players: Brian O'Driscoll, Gordon D'Arcy, Sean O'Brien, Johnny Sexton

University of Notre Dame Fighting Irish Rugby
    Based in South Bend, Indiana
    Competes in College Premier League and D1 College Rugby

Irish Rugby Football Union
    Ireland National Team
    Competes in RBS 6 Nations, Rugby World Cup, and International Test Matches
    
United States of America Rugby
    United States National Team
    Competes in 7s World Series, Rugby World Cup, International Tests, Churchill Cup, and more.
    
Northern Virginia Rugby Club
    Based in Northern Virginia
    Men's USA D1 Club
    Competes in Mid Atlantic Rugby Football Union