Kenpo kai Karate

To me, Kenpo kai has one of the coolest back stories in martial arts.

There was a Shaolin monk named Chian in China.
His family's home was getting robbed over and over again (who in their right mind breaks into a Shaolin monk's family's house?), so Chian taught Shaolin Kung Fu to his family and the style became known as "Chian Quan" (boxing of the Chian family) and was handed down in the family.
Years later the family took in a Japanese traveler named Tawada Ishizaka, who was skilled in the art of Kashima Shinto-ryu.
Ishizaka stayed with the Chian family for 20 years (evidently when a Chinese family takes you in, they REALLY take you in) and as a member of their household he was taught Chian Quan.
He eventually left the family, returned home to Japan and modified the style creating his own style called "Ishizaka Ha Kenpo" (boxing of the Ishizaka family) and it was in turn passed down through his family.
Many years later in 1967, Kazuo Ishizaka and Sotoki Ishizaka went to Shanghai to recover old martial arts forms and techniques lost with time.
They found Hou Rou Chian, who had inherited his family's art and trained with him for two years, then returned to Japan.
Since the style was originally Chian Quan, they didn't feel right about calling their style Ishizaka Ha Kenpo, so they created the name "Kenpo Kai" or "society of the fist method."

For more info you can go to the International Kenpo Kai Organization's site here