‘Comedian Stewart Lee’ writes in the Guardian on German humour. This analysis arises from a trip to Germany with Richard Thomas, who wrote Jerry Springer the Opera, who was commissioned to write a musical of that type set in a British stand-up comedy club which then had to be translated into German. (Why am I laughing already?)
Lee says that Germans do have humour, but it is hard for us to recognize, and vice versa. He claims that English humour is facilitated by the English language. Putting verbs at the end of the sentence and using a lot of compound words kill humour, he says (apparently seriously). He now concentrates on the humour of ideas:
On my first night in Hannover I had gone out drinking with some young German actors. “You will notice there are no old buildings in Hannover,” one of them said. “That is because you bombed them all.” At the time I found this shocking and embarrassing. Now it seems like the funniest thing you could possibly say to a nervous English visitor.
At all events, Germans are invited to submit their own jokes in English, to show there is German humour. The four quoted have failed to do this. (Thanks to Trevor for the link).