Fick dich ins Knie!
German expression meaning "fuck off" or just "fuck you", literally "fuck your knee". The origin of this expression is a pun with the archaic word "Kniefiez", meaning a very avaricious person such as Scrooge McDuck. Therefore, its original meaning was "If you're to cheap for that, you can go and fuck yourself.". However, with time it has become a more general expression that could be used equally well in any other context.
100 Mark für einmal kurz blasen? Fick dich ins Knie!