The group in Den Haag is coming together today at 18'30. The meeting point is under a tree going out the centraal station direction Marieveld. It's quite easy to find. Here the Facebook event: https://www.facebook.com/event.php?eid=185036238216678
There are people from Leiden and Delft that come together there. And a few people from Rotterdam started joing also in the last assembly. The assemblies are in a weekly basis, sometimes on Wednesdays, sometimes on Sundays.
The main communication mean is the Facebook group, as far as I know: https://www.facebook.com/home.php?sk=group_202620699774029 They also have a group in Agora, but not very active these days.