A very good business is to create a center of Martial arts: Different types of Karate, yoga, Thai Chi Chuan, Along with a shop with accessories for the practice of these disciplines, and products that consume those who practise them (clothes, footwear, alternative therapies), a bookstore and thematic video library faced to the topic in question.
Periodic conferences of teachers or recognized teachers, exhibitions, classes and conferences on self-defense, testimonies of those who practise them, can transform to the world of the martial arts in an extraordinary business.
If you want to initiate a proper business and the martial arts excite you do analyze this interesting idea of business. Especially in the big cities there exist many followers, practitioners and fanatics of these disciplines.
There is nothing better than to tackle a business based on anything that you like, it is a guarantee for the success.