I've been super ahhhh busy - and haven't had a chance to sit down and gather some of my favorite places in Berlin for a friend's trip. I finally did! There are a ton of other places I love, but here's short short list of some post in Kreuzberg/Friedrichshain:
Kunstraum Kreuzberg/Bethanien - cultural center with various art galleries and orgs in a history hospital
Club der Visionaere - river side bar
Balkan Tripps - ping pong bar on Glogauer Strasse
Kaufbar - super cute cafe
Kosmonaut - club
Görlitzer Park - park
Treptower Park - another park
*drink Club-Mate with vodka, eat döner kebab, explore abandoned buildings and ride bikes everywhere*
Now go get lost!