Kempo (Kenpo) Karate. All four Wing Chun schools that I've visited seemed to spend a lot of time doing blocks in horse stance. I'm sure there is a practical application for that on the street, but I don't know what it is.
Edit:
It wouldn't surprise me a bit if they weren't legit. It seems like just about anybody can put anything up on a sign. It was actually really funny. This fat guy with a white beard and a Confederate rebel flag bandana kept leaping towards them yelling, "10 sow" "10 sow" at the top of his lungs, then he lept towards me and yelled it again waiting for me to be awed. It was very strange.