yeah, I had to google to find out who wrote the music, I knew it sounded familiar just couldn't place it. Then I find Bobby Sands wrote the lyrics, gives me mixed feelings on that.
like the song you posted, but I would say the instruments at the top of my list to learn are fiddle and bagpipes.
This video is super cheesy but this is my favourite polka. I love dancing to polka, it's just so fun. It seems this only happens at weddings though.