Simon has been busy! Since last autumn, he has organized Hantverksklubben (roughly, "handicrafts" or "hands-on" club) here in Sweden, through the Rollspel.nu forum and conducted at the Hem-Con Discord server. All of this is in Swedish, but I'll say more about that in a moment. As of the discussion presented in the video, they've played 19 sessions, no small feat considering what they're doing.
Simon describes it fully in the video, but briefly for text here, this is an open group which meets to play with deliberately no preparation. They arrive at a few parameters of play through discussion for a little while, then play for about an hour. Once done, that's done, and the next meeting starts from scratch.
From my perspective, without any implication of project or product-oriented workshopping, they are fully engaged in game design - of the right kind. I've designed all my classes in the context that design is a subroutine of play, and practically simultaneously with that coursework, that very principle has been enthusastically in practice, as organized by one of the best qualified persons to do it whom I know.
Anyway, watch the video. I disclose fully that I was skeptical - when Simon told me, "yeah, we're meeting with no GM and no mechanics," the chorus of differently-toned alarm bells in my head was deafening. But then again, I've played several of his games, and there is no shred of no-rules blither in any of them ... so I said, "let's see what you mean." As it turns out, it means a lot.
Last point: Simon is also offering to help and participate with anyone who'd like to do this in English too!
(dammit, I misspelled it in the videos. I'll fix that as soon as I can)