Not sure what to make of this but thought I’d put it up for your attention. Improv Everywhere is based in New York and
causes scenes of chaos and joy in public places
You may remember them from such missions as the rather wonderful Frozen Grand Central
Anyway, there are a couple of local spin-off groups, the most ‘active’ of which seems to be the West Midlands group on the Urban Prankster Network, although there hasn’t been any activity there for the past couple of months. There’s a Facebook group too, but that’s a closed affair so I’ve no idea how vibrant or otherwise it might be.
A bit of a flaky post info-wise, I know, but if you’re interested in this sort of thing those links might help you get started.