During a summer job (12+ years ago) I helped install some in someone's back yard. We installed the EcoGrid and seeded over top of it. The idea was when his mother in law was visiting, he could drive her around to the back door (only door with no step) to let her in. The rest of the time it just looked like the rest of the lawn. As far as I know it worked out really well.
I've also seen that used around driveway aprons where semi trucks have a tendency to drive off the road and onto the grass. Keeps the grass from getting rutted, don't know the name however.