My dojo had been without mats for so long that we had pretty much gotten used to training on thin commercial carpet on concrete. When we went to a workshop on Florida's other coast, I and another student found ourselves without room to work comfortably on the mat. So we moved over a few feet and started throwing each other around on the linoleum floor. The rest of the class looked at us as if we were from another planet.
Robert and I just continued hitting the floor with a smile.