I love this restaurant:
http://www.landersdorferundinnerhofer.de/

It's a fine dining place, but the decor and ambiance are rather plain and normal.
They don't have a dinner menu, it's all "surprise". They ask you if you have any aversions or allergies, then they keep you bringing food. It's about 8 courses, but they don't rush your at all. It's perfect for a good time: you eat, drink, talk, then eat some more...
They ask if you are ready for the next course, and what kind of "protein" it's going to be. You may choose to skip it, or get an optional dish. Between the seafood/poultry courses and the red meat courses, you get an unbelievably delicious basil sorbet.
The downside is that it doesn't open on weekends. It's downtown (Marienplatz area), maybe that's why.