BB it's all about the severity of the joke, if it's implying that a people are stupid, or drunks, or thieves it's worse than someone going on stereotypes
Okay...I get what you mean!
I'm not sure how to go about I just know from experience that our own turkish/arab comedian who makes a living on playing all possible stereotypes between Arabs/Turks/Germans/Italians/Greeks and so on did more for a better image of Turks with the Germans than all lofty sunday speeches by politicians.
I just think doing the indignant/protest ritual every time somebody makes a joke does NOTHING to better your image.
Poland should really take the mickey out of Germans in the same spirit...I know it worked with our constant mockery rival the English (and the Dutch). That was really mean once but got now much better...