I had a friend who was, and i found it so fascinating! We would find yucca plant sticks and cut them to length and he began showing me a little. He moved on though, and I never stuck with it. The focusing part was astounding once I figured out what he was talking about. I used to walk through the pasture hunting bugs on the flower tops.
Wish I would have stuck with it and found proper training.
I've been interested in a few of the martial arts such as muay tai, capoeira, and krav maga. SWMBO and I have talked about it some time back, and intend on putting our daughter through something when she gets a bit older.