Vienna is a great place to spend outdoors, hiking around the Kahlenberg, or one of the many city parks. I am a member of a local tennis club, so I can recommend you places to play tennis. The park behind the apartment, Augarten, is a great place to go for a walk, run or just chill with a picnic or one of the cafees there. You are also just 15 minutes walk along the Donau canal to the center of the city - Schwedenplatz.