I found this film quite irritating for the first 20 minutes or so (think perhaps John Cleese in Clockwise), but something told me to keep watching, and I'm glad I did. I'm told the humour is Irish, but as an Englishman I found a lot of it pretty funny, and there's some good role reversal work in the story.
I was expecting an Irish version of the Hangover (not a bad thing), but instead got a hilarious, touching, original piece. Laughed out loud as did my wife. Rent it.
Being Irish I got a lot of the humour in this film. From the strange Irish names to the typical group of Irish culchie 'lads on tour' who do not know how to react when they meet a street-wise macho-man! I found some of the scenes hilarious - watched it with my mum who thought so too! Overall 3 out of 5 - not the best comedy I've ever watched but again the Irish wit and charm won it for me!