One of my favorite places in Amsterdam. I recommend taking the elevator to the top floor and then walking/ taking the escalator down. The cafe up there is great- food, juice, you name it. The roof deck outside gives a great view of the city. There are lots of hidden nooks on each floor- I discover something new every time I visit.
Website: http://www.oba.nl/
Address: Oosterdoksstraat 110, 1011 DK Amsterdam