Oddly enough, Soviet Union had a thing similar to "Kimchi Harvest". I remember workers in my town having to go work at a collective farm for a week harvesting things.

They also had something called "subotnik", aka voluntary Saturday labor. This was a practice where citizens, including workers and students, participated in unpaid labor on Saturdays. These activities included various tasks like cleaning up the city (that's what I remember doing as a kid). There was nothing "voluntary" about it.