During the last hollidays, I went to Wien with a association which deals with Ecole centrale Paris.
With some friends and some teenagers like me, we went to Wien during 5 days. It was WONDERFUL!!! I think that I have passed the greatest hollidays ever.
We went to Wien by bus, so ok it was not the most comfortable and fastest way to go to Wien, but it was quiet cool.
During those three days we walked a lot in the city. We visited a lot of things like the stephamsdom, some museum like the albertina or the bleveder, Schonbrun or haus der musik.
We slept in a youth hostel in the city center.
There was a very good ambience between the whole group since the escort were 20-25 years old so they were very cools with us and we were independants.
The only dark side of the travel was that I don't speak German at all so it was quiet hard to understand and to be understood.