We visited in China some art exhibits with mainly Chinese peasant painting, a movement started with the cultural revolution and the program to impart art education to peasants in China's villages. The result was a generation of peasants painters which reached national and international fame and whose art is featured in many Chinese museums.
About Chinese grass-roots art read more here.
I made a slideshow with some of this art that you can see on my page: Naive painting.
Here are my favorite paintings.