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!
Boutique space offers natural perfumes, organic soulful objects, Japanese crafts/ceramics and antiques, natural incenses and smudges, resins and wood pieces for burning in incense ceremony. There are also Chinese tea ceremony going on Saturdays, zen meditation, scent-related soirees and other workshops.
Kw is a great art institute situated at the backyard of a very eastern part of town, place for many other small galleries. Auguststrasse is worth the walk and Kw is worth the stop.
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.