Apart from physics...
...I enjoy sports such as running, biking and swimming, and I love to dance, in particular Bhangra and Lindy Hop.
If you ever feel like running a half marathon, I recommend the one in Heidelberg, which is quite hilly but makes up for it by providing the most beautiful surroundings.
Regarding biking, have you heard of Vätternrundan? 300 kilometers all the way around Sweden's second largest lake in June when it never gets dark!
In case you enjoy sailing, I know a great organisation that offers affordable sailing trips for young people (website in German):