Yin and Yang
Was Never So Much Fun
Hier to the School of
Anything Goes Martial Arts
Ranma Saotome, the well-built hero/heroine (sort of). The martial art of kempo is his life. Never turns down a challenge (martial arts rhythmic gymnastics, martial arts skating, martial arts tea ceremony, martial arts dinner, martial arts cheerleading, and so on... if it has "martial arts" in the name, he'll win, eventually).
Training with his father at the mysterious Jusenkyo training ground in China, he was thrown into a spring called Nyanniichuan, where a young girl drowned 1500 years ago. He emerged as a young girl, according with the spring's curse. When splashed with hot water, he changes back to a boy, but when splashed with cold to room temperature water, he turns into a girl again.
By their parents' arrangement, Ranma is engaged to marry Akane Tendo and become head of the Tendo dojo. But neither party wants to go through with this arrangement.
Ranma ½ Info Site