If you are looking for things to do while not in the dojo, you should be aware that the Stockholm Culture Festival is ongoing. Of course this is an option for anyone coming along but not joining in the dojo too.
There are all kinds of activites ongoing and too many to list here. However, there is outdoor cinema, park theatres, concerts to attend. Additionally, there is a lot of stuff you can try out such as breakdance, high-heel dancing.
The program is published here, in Swedish but google translate can give you an English version.
The area of the city where the festival is is shown on this map.