One note is that on different albums, they have different versions. Not only are the verses different (one verse is different, really, and some of the words here and there in the verses that are the same), but they manage to do it in a kind of inside-out rhythm that, having learned the first one (The Boys Won't Leave The Girls Alone, I think), I found it almost impossible to sing along with the second (which I think they did with Robbie O'Connell rather than Tommy Makem). I can't explain what I mean by inside-out rhythm, except they seem to do the downbeat where they did the not-downbeat on the other. Or something. If anybody could actually EXPLAIN to me how they do it, I'd be very interested, I can't figure it out.