I downloaded gg_geo_pfxhair geometry shader, i found some info about it here on cgtalk. I read that you have to write a command which exports a sort of hair cache. then you attach the geoshader to a placeholder object, like a polycube. finally you have to point the path of the hair cache in the shader.
I didn't get it to work though. I don't know how to write correctly the path.
You can find the related discussion about this shader here:
and more here:
Has anyone succeded working with it?