Champaign-Urbana is a center of Taiji practice today in part because one particular person, Yang Yang, came to UIUC from China to do doctoral research that would use scientific methods to establish that taiji practice was good for your health.
Working with seniors at Clark Lindsey VIllage, he succeeded. One outcome was a new seven part Taiji form that is easy to learn but comprehensive in its movements and effects. Another outcome was a Taiji community that has survived his departure for the East Coast: Center for Taiji Studies: http://www.chentaiji.com. Yang Yang's student and the Center for Taiji Studies co-director Scott Grubisch teaches classes at IMC in Urbana.
Also longstanding is Master Song's Academy in Champaign. And a long running Taiji class at Urbana Park's Phillips Recreation Center.