The best cheeseburger in Berlin costs less than 5. Burgermeister is mandatory in town when you're craving for a basic and delicious to the bits chesseburger.
Flughafen Tempelhof was once the symbol of nazi-pride when Hitler notoriously comissioned construction of the smallest duty free shop in the world (and a beautiful example of fascist architecture). After the war, Tempelhof became one of the frontiers of the cold war with the U.S. battling the communists (who undoubtedly wanted to get rid of the small duty free shop altogether) via the Berlin Airlift. It turned out to be a huge succes, and enabled the allied forces to remain their presence in Berlin and save the small duty free shop. The real free-market victory will come in about two years though, when project developers will take over and start building houses, blocking my view onto the airfield.
There's nothing more revigorating during the dark winter days than spending a couple of hours in a sauna. Germans have mastered the art of sauna and you can find amazing pieces of architecture in the public swimming pools (Stadtbad). I find Stadtbad Neukölln very peculiar in its neoclassic architecture and it's definitely a wallet-friendly option to enjoy some sauna time there. Be prepared to be naked in front of man and woman!
Peres Projects mostly showcases young, emerging artists and is at the forefront of fusing art with fashion, celebrity and the love of a good party, which seems to work very well in Berlin. Having recently moved into an ex-Soviet building on Karl Marx Allee, the giant new space contrasts brilliantly with the commanding facade.