We visited two buildings by Hundertwasser, an artist/architect who is very popular by the public, but disliked by most of my fellow colleagues. His architecture is flamboyant, chaotic, anarchistic and very colourful. Even though it's far away from my architectural taste, I thoroughly enjoy his visions. But I would hate to have to live in it.
Anyway, we visited the "Kunsthaus Wien", which has a nice terrace in the backyard. Shaded trees, colourful architecture and good coffee. What more do you need for a decent sketch?