While strolling around Mitte, check out the flagship store of Berlin´s cult women fashion brand. (And try a delicious cinnamon bun at Zeit für Brot next door.)
New type of museum. It's a private collection from contemporary art pieces such as by Anish Kapoor or Nobuyoshi Araki to Chinese imperial furnitures or ancient Asian sculptures. The collection is wonderful and the light design is perfect. There is no description or title of the artworks - it invites you to purely see/feel the artworks themselves without influencing by the names. Must to go.
A very close friend of mine owns this bar. It looks tiny from the outside, but it has two rooms you have to pass until you get to last one which is a discofloor. I play music there from time to time and I am always surrounded by nice people und friends.
My favorite lake to visit during the warmest months. It's located in the southwestern part of Berlin and it's reacheable by public transportation, just around 40min from the city center.