Tai Chi regarding as one of the best exercise for balance improvement, the meaning of
improvement of this ability can foresee fall prevention. Also the Taichi is also good for coordination, and build self confidence. Since it is also easy to operate, many senior center have regard it as a regular course for most senior participants.
You can find some of there list here in California.
Pasadena Senior Center(Link)
City of Benicia(Link)
City of Irvin (Link)
Ukiah Senior Center(Link)