In such a huge and cosmopolitan city here are some guide websites and some hints to check all the events calendars , to buy tickets online and to simply orientate especially if you are here for few days...
The best site where to buy tickets for every event ...from concert to theatre to opera and to find the latsest news about all the venues.Click on the english version of course...
The best site for expats and for tourists : full of news and info about the city and what is happening every day and night ...