I'm changing the date of this event to the 10 of August, because I believe that is when the best musicians will be playing on stage.
9-11 of August there will be a great Folk Music Festival at Hesselby Slott. There will be a lot of great musicians on stage, and a lot of jamming going on in the area. Don't miss this great opportunity if you are in town. Bring your own instrument if you have one and join the jamming.
How to get here: Take the subways green line towards Hässelby Strand. Get off at Johanneslund. When you exit the subway station, turn right and go under the subway bridge. Go straight until you arrive at a big roundabout. Cross the roundabout and follow Malteholmsvägen on the right. After a while you will see the castle on your left hand side.
Meeting point: Outside the entrance
Tickets: Buy your tickets online at Ticnet and print it.
Unfortunately there is no information in English, but here is a link in Swedish with the schedule.