There's these four Irishmen in a bar, all drinking Guinness. One of them is looking rather puzzled, so another turns to him and asks him what's the matter.
1st Irishman: Well, I was just trying to remember what 2 plus 2 is. 2nd Irishman: Oh, that's easy, it's 147. 1st Irishman: No no no, that can't be right. How about you, Fergus, do you know what 2 plus 2 is? 3rd Irishman: Hmmm ... could it be Wednesday, perhaps? 1st Irishman: No no no, that doesn't sound right either. How about you Pat, do you know? 4th Irishman: Simple, the answer is 4. 1st Irishman: Of course! How did you work it out?! 4th Irishman: Aha, that's where brains come in! I subtracted 147 from Wednesday!