Dropkick Murphys, "The Warrior's Code": If you've listened to any Dropkick Murphys songs, then you already know it's pretty damn hard not to want to be Irish-American after listening to their prideful, politically loud Celtic punk anthems. You also know they really like The Pogues. The Pogues, "If I Should Fall from Grace with God": The original Celtic punk rockers, The Pogues got famous thanks to the stage antics of stereotypically falling-down-drunk frontman Shane MacGowan. Oh, and their music, too. The Frames, "Revelate": If you've seen or heard the music from Once, then you're already familiar with Frames frontman Glen Hansard. The band vacillates between haunting ballads like those found in the movie and the kick-ass rock jams they perfected throughout the '90s. Flogging Molly, "What's Left of the Flag": Flogging Molly is an L.A.-based Celtic punk outfit just as catchy as the Dropkick Murphys, but less angry. A lot less angry. Instead of making you want to fight, they make you want to drink and sing along. My Bloody Valentine, "To Here Knows When": Ear-splitting shoegazers My Bloody Valentine was alt-rock way before Seattle teens hopped on the bandwagon. The legendary band went AWOL in 1997, but returned a decade later to a fan base still clamoring for their music - and still has yet to follow up its 1991 masterpiece Loveless. Damien Rice, "The Blower's Daughter": Damien Rice's haunting ballads have the unique characteristic of sounding utterly romantic and utterly suicidal at the same time, which is probably why the ladies love him so much. He's like a Shakespearian sonnet with a piano backing track. Stiff Little Fingers, "Gotta Gettaway": Punk-rock legends from Belfast once called "The Irish Clash." Led by Jake Burns, a dude who sounded like he gargled with glass shards, Stiff Little Fingers often got political, but never got great again after their first couple of records between '79 and '81. U2, "Where the Streets Have No Name": We saved the biggest for last. If you don't know who U2 is, you're probably a member of one of those lost tribes in the Amazon. And even then, we don't believe you haven't heard of them.