A good place to drown your Berliner winter-melancholy. The bartenders are top notch and the interior is warm but stylish, with the inevitable retro vibe. Open from 6 till late. There´s also a legendary (and kinda expensive) restaurant next door, which provides the bar with some excellent snacks. Works for dates and for friends, but if you´re planning for a bigger group it might be wise to reserve.
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!
This museum of photography is really great, and the highlight for me after the inspiring exhibitions is the good coffee and great cakes at their coffee place.
I find myself there almost every second week for a drink and a slice of cake. The food is perfect, the ambiance is nice and it's really alive as a lot of people are coming directly from the running exhibition. At the entrance you can find an interesting bookstore and the best photoautomat of the city right outside.
Last but not least, it's only some meters from the Helmut Newton Fondation ( which doesn't have a nice coffee place itself yet ).
I never heard about Havel until some friends and me checked out the google earth for a trip at the weekend. We went there in the german winter, oh yes...in the winter. I loved this place because is a small city island with a lake (which was frozen at that time) and with lovely houses and an old mill. I have never been there in the summer but i can imagine how wonderful would be.
Tuesday's lunch hour tip is the amazing Berlin Philarmonic. A short-duration concert (around an hour) happens every Tuesday at 13h, for free. People make the Philarmonie's foyer full, sitting on the stairs, on the ground and everywhere around. Little advice: bring with you a little cushion for more comfort and try to arrive early to find the good spots.