UiO has Norway's greatest collection of Art. And many of the most visited museums in Norway, like the Viking ship museum. Go around in the institutes and look for art. Only Faculty of Law is downtown. The others are at Blindern where your Summer School mostly will take place.
International contacts are very important.
I really hope that you will understand Norway and Norwegian lifestyle better after this summer. And have lived in Oslo except for a few years in USA, and several visits to many countries in the world. First a little about our summer. Usually nice weather in Oslo. Better than you have experienced so far.