MLB.com has a good story on Kenichi Zenimura, popularly known as "The Father of Japanese Baseball" for his efforts to keep baseball alive and thriving for Japanese Americans in internment camps during World War II: Baseball cast light in shadow of war. He died in 1968, but 2005, the governor of Arizona decreed the observance of Zenimura Day in honor of his achievements. MLB.com also ran a similar story on Zenimura last year: Zenimura a true baseball ambassador.
If you're interested in the story of baseball in the internment camps, I highly recommend checking out the movie American Pastime
, which has elements that are loosely based on Zenimura's story. Featuring rising stars Aaron Yoo and Leonardo Nam, it's a sort of Hollywood-ized version (in a good way) of the internment camp baseball story. Very entertainment and heartfelt. I'm a sucker for inspirational sports movies. Throw in the internment camp aspect, and man, you've got me. Heck, I'm sort of getting choked up just thinking about it. Anyway, it's a really great movie.