They opened a swap shop where you can listen to over 100 mixtapes and take away any of them, in exchange for another tape. Each month they have a Tape of the Month which is always one that is different from most tapes in one way or another. They also host live music once a month and have a cafe in the back room where they sell beverages, snacks and newspapers. I think the latter is how they pay the rent for the store.
I think it is a brilliant idea and will post them one of my tapes, whether I get one in exchange or not. For any additional info on the store (mostly in German though, I'm afraid) go to their web page.