A few other random things that have caught my eye:
An old East German watchtower, preserved in what is rapidly becoming a residential district.
View of Fernsehturm, from Museum Insel
German couple, out for a stroll on Karl-Marx Allee
Potsdamer Platz train station
Some little kid riding a super-cute, wooden bicycle through the train station. He refused to get off the bike when going down the stairs, forcing his mother to pick it--and him--up and carry them down to the lower level. Once released, he sped off with little regard for passersby or his own safety.
Biergarten Prater, one of the oldest in Berlin. Prater Schwartzbier, yum.