My Austrian Roommates in Warsaw

So I moved into my hostel here in Warsaw - I am in an 8 person dorm and I was the first person to move in. The last time that happened I met up with 3 cool guys from Nevada in Vienna. This time is really different. Apparently 7 girls from Vienna (yeah that sounds good.....) decided to take a 5 day trip to Warsaw (why so long only God knows). I asked them where they were from and they said Austria. Now, I've just left Germany hoping to get out of the German game for a while, and look what I have to deal with. You would think having them all in the room could have it's plusses, but really doesn't. They are probably 18-20 and act like it's a slumber party every night. Uncomfortable you know? But the thing is, I never told them that I knew German. ;) . So for three days now I've been just listening to what they're saying, and really it's sad that people can talk about such stupid shit for so long. I just got out of my room for example and they were arguing whether or not the "the" for "Cakes" is "Der Cakes" or "Das Cakes"... If I didn't know German I would definitley be losing it right now.

Here's the thing. I've been giving them small clues to the fact that I know german. They wanted me to sign their shoe (yeah. they're wierd. i told you) and I put Mark, aus den USA. They didn't read it until the next day for some reason and they were like.. whhhatt.? (or it was probably like "Waaaaas?) and then the other day I walked in my room with them and asked them "Wie Geht's?". They all kinda giggled and answered.
But they kinda caught on because I was listening to their conversation one day and they thought that that shouldn't be happening. They asked if I knew German, and I said just a little.
But tonight I said a few sentences in German and answered a few questions which they asked each other in German.. they asked if I studied it in highschool or something. I told them I studied abroad in Stuttgart... and I finished 6 days ago.... HAHA... he look on their faces was hilarious. They had no idea for 3 or so days. They were all in disbelief and laughing, thinking about what they said when I was around.

The reason why I kinda did it was 1, I was tired of German. 2, for the last year I've had to expect that everyone around me regardless of who they were or where they came from understood me when I spoke English. z.B. the Finns don't have that problem for instance --- they told me they regularly make remarks (for example) about the stewardesses in planes when they're right in front of them.. I mean who knows Finnish except for the Finns. So this was the first time that I could actually do it. Kinda fun actually.