Around Boxhagener Platz or simply Boxi, you find lots and lots of cafes, pubs and bars, for example good burger at Burgeramt or delicious falafel at Ali Baba. There is also the very Berlin-like living room cinema b-ware!. In contrast the former DDR Kino International is a very noble, architecturally interesting cinema. For more impressions of classic DDR architecture walk along Karl-Marx-Allee and Frankfurter Tor.
Of course Friedrichshain is best known for the many techno clubs around the Spree, like Kater Blau and Berghain, but there are so many clubs all over the city, like Watergate, Sisyphos, Hoppetosse, Arena Club, Bi Nuu, Club der Visionäre, Ritter Butzke, Wilde Renate or About Blank.
Around Helmholtzplatz you experience a more calm, local Berlin. Shop for cute presents at Victoria met Albert or go to cozy cafe Suicide Sue. For a very good but simple dinner eat at Salt n Bone.
The Dong Xuan Center is Berlin’s biggest Asia Market, where you simply get everything from food to cheap shirts and plastic flowers.
The viewing platform of the Teufelsberg is a surreal place like just out of a movie. It was a former US listening stations right atop the hill and now is an abandoned graffiti-covered building. You also have a nice view of the city, but if you don’t have a car it takes fairly long to get there and for now the ruins are forbidden to enter due to security reasons. Especially in spring and summer the Pfaueninsel and Schloss Charlottenburg are lovely getaway destinations.