TaiChi and Qigong are mind/body exercises which are based in traditional Chinese martial arts. Qigong translates roughly as cultivating the inherent functional essence of the human being. TaiChi translates as "Grand Ultimate" which refers to a natural state of dynamic balance.
Both TaiChi and Qigong have been used extensively for thousands of years for healing, stress management, longevity and meditative purposes. There are hundreds of variations of each form and there is quite a bit of overlap between them.
Modern research supports their healing functions and both are becoming more and more mainstream as word gets out.