The German phrase my brother and I constantly throw at each other is “Deine Mutter ist ein Tageslichtprojektor”. If I ever get into a verbal fight in Germany, that’ll stop it for sure.
(translator’s note: According to a German friend, they don’t call them Tageslichtprojectors in Germany. I have no idea where my textbook came up with the word. But it’s more fun to say than das Overheadprojektor)
Well, living here in Japan with the World Cup going on, I hope I never have to say: “Omawarisan, gokai desu. Watashi wa hooligan dewa arimasen”. (Translation: “It’s a misunderstanding, officer. I am not a hooligan.”)
A friend who used to work with military intelligence (insert compulsory oxymoron joke here) once taught me how to say in Russian: “Don’t shoot! I know secrets!”
Unfortunately, I’ve forgotten it.