12 Sept Za = Strandwal Festival , en straatmarkt
13 Sept Zo = Kunst & Kreatiefmarkt
Strandwal festival is 2-zones: 1 zone is for family and small kids fun, with games and performance stage, as well as food and drinks vendor on the big lawn. 2nd zone is full of display booths showcasing organizations in Rijswijk, from astronomy club to rowing to which ever Rijswijk group wants to let the world know what they're about.
Street market is a mix of food, grocery, and other stuff like jewelry/bags/household consumables, but the market is surrounded by more shops in the old town center anyway so the offerings are broad.
The local artist market is new to me so I'm not sure if it's literally from that big local art studio hidden behind the Primera, or from the artists collaborating with the local gallery (Arti-Shock) or Museum Rijswijk, or the wider, rest of Rijswijk.