It's a Tango dance spectacular. You can read about it in German here http://www.mqw.at/de/programm/detail/?event_id=7460&filter_keyword_ids=16
I couldn't find anything in English, but hey, what else do you need to know? It's Tango, it's hot, it's cool, it's Christmas, you owe yourself a fancy night out so let's go! :-) Tickets cost 47.50EUR. If you want to go, sign up, contact me and we'll arrange for me to buy a block of tickets so we are all sat more or less together. No backing out once the tickets are bought!