One of my favorite stations on Pandora is my Celtic Punk station.  It was inspired by listening to the waiting music on a friend's Nextel phone; he had the Dropkick Murphys, a great sounding punk band that just reeks of the old country.  Other bands include the Pogues, the Tossers, Flogging Molly, and more than I can think of.  Forget Riverdance, this is the stuff.

In celebration St. Paddy's, here is one of my favorites: