The costumes, by the way, are called "dirndls", and while it is apparently possible to wear a dirndl with a high-necked blouse, it's unusual. As for the traditional Muslim costume, that is right out.
Here are two traditional German Oktoberfest Girls, one wearing Tyrolean hat:
Here is a picture of a girl and some large steins of beer. (At Oktoberfest they serve one-liter steins of beer—that's almost 36 ounces.)
It's all very comradely and traditional:
This Festival is so German, in fact, that I was a little surprised to see the second girl from the left, here, who is not apparently not 100 percent German:
There are only 800, 000 blacks in Germany, amounting to less than 1 percent of the population. This, as I noted a while ago is because Germany did not import slaves in the 19th century. But this girl has assimilated to German norms as far as the traditional Oktoberfest costume is concerned, whereas a Nigerian girl in England had to be sent home from a waitress job at the Savoy Hotel because she insisted on wearing a hijab. (Pictured right—the traditional costume of a Savoy Hotel waiter as worn by Britney Spears.)
By the way, if you're interested in traditional German culture, as exemplified by the girls of Hofbrauhaus, below, many more pictures of Oktoberfest girls can be found here.