Inside the old Kurhaus of Semmering you can see a special kind of theatre, not in an audience like in an ordinary theatre, but you will sit in the reception-area and other places of the former hotel and will watch the play going on, telling stories and episodes of the life of Alma Mahler.
Alma Mahler (1879 - 1964) was a real person of Austrian history, a "femme fatale" who had plenty of lovers and husbands, umong them celebrities like the composers Gustav Mahler and Alexander Zemlinski, painters like Gustav Klimt and Oscar Kokoschka, the architect Walter Gropius and the poet Franz Werfel...
in 1910 she had a summerhouse built in Breitenstein, close to Semmering.
read more about this theatre & performance at my link below, unfortunately only in german, BUT you need to be able to understand german anyway for that kind of theatre !
Dress Code: The first real problem for the ordinary tourist will be to get one of the rare tickets, and in case you get them, dress elegantely or in any "extra-ordinary way", simply in a way that would "fit" to the performance...
In Reichenberg an der Rax you will find one of the most interesting theaters of Austria, simply because it is there, where most of the famous actors of Burgtheater, Josefstadt and many other theatres of Vienna will stay in summer and will make the performances of the small theater something special.
Dress Code: Dresscode is not so very strict, BUT you will see more people dressed formally there, than in many theatre-performances in Vienna. People coming to the theatre of Reichenberg are somehow similar to the ones going to the Salzburger Festspiele : the walk to the theatre in fine robes and the breaks with champagne and chats with the celebrities is somehow more important than the performance of the theatre itself...
I had a look at the ticket-box and saw that all performances were fully booked for summer 2007 !!
What could be a better place for a theatre-performance of Hugo von Hofmannsthal's "Der Schwierige" than the old Suedbahnhotel at Semmering, a place that's time was over a long time ago and only a bit of its former glory and atmosphere is shining through here or there. The main theme of this play is the coming end of the noble life of aristocats during WW I, while the world around them is changing, but they will not realize.
Dress Code: This theatre certainly requires a formal dress or at least something "fancy"
This is a link I found for german-speaking tourists:
Semmering is an important mountain station,
very much frequents from tourists.
In the evening, the whole station is a splendid magic place.
The skiing track is a collection of lights, lives, colour, laughter, and sport.
The restaurants and bars are full with guests that enjoy the good food, or warm with hot beverages.
Directly on the ski run, the tourists can drink hot mulled wine or tea.