The Olympic Park from the 1972 games, is still very much alive with activity. Today concerts are held in the arena and the main stadium also hosts sporting events. The funny thing to me was that although it was an Olympic venue, there are no Olympic rings to be found anywhere and if you didn't already know about the Olympics being held there, you'd be none the wiser just looking around.
There is a communications tower that was bult there even before the Olympics and its worth the 5 euros to go to the top and get a nice view of the city and on a clear day, the Alps. There is also a mini rock and roll museum. You can catch one of the subways from downtown right to the place!