INSOMNIA.
Insomnia is a growing problem in our rushed digitized world. T'ai Chi & Qigong Students often remark of improved sleep and reduced insomnia after a few weeks of regular Tai Chi and QiGong practice.

Sleep problems. In a University of California, Los Angeles, study of 112 healthy older adults with moderate sleep complaints, 16 weeks of tai chi improved the quality and duration of sleep significantly more than standard sleep education. The study was published in the July 2008 issue of the journal Sleep.
Harvard Medical School's Health Publications, May, 2009

According to UCLA researchers, performing Tai Chi improves sleep.
In UCLA a controlled study, the Tai Chi group, practicing two hours of Tai Chi per week, left 63% of the Tai Chi group with improved quality of sleep. The control group practicing only healthy habits, but no Tai Chi practice, left only 32% with improved quality of sleep. Tai chi alone doubled people's chances of improved sleep patterns, over simply adopting healthy habits. (Source: ConsumerReportsonHealth.org). 
Tai chi participants had significant improvements on five of the PSQI subscale scores (sleep quality, sleep-onset latency, sleep duration, sleep efficiency, sleep disturbances), PSQI global score, and ESS scores in comparison with the low-impact exercise participants. Tai chi participants reported sleep-onset latency of about 18 minutes less per night and sleep duration of about 48 minutes more per night than low-impact exercise participants. Tai chi participants also received better scores on secondary outcome measures than low-impact exercise participants. Both groups reported improvements in SF-12 mental summary scores.
-- Journal of the American Geriatric Society, 5, 892-900

At the QiGong Department of Ningbo Hospital of TCM, in China, they gave 78 patients suffering from insomnia, treatments involving QiGong Meditation (Sitting QiGong), coupled with QiGong self-massage of several acupressure points including in the wrists. After one course of treatment, 35 cases were cured (good sleep for more than 6 hours a day, no concomitant symptoms any more), 22 cases showed obvious effect (sleeping for 4-6 hours per day with other concomitant symptoms ameliorated obviously), 9 cases showed some effect (better sleep than before with other concomitant symptoms ameliorated a little), 2 cases showed no effect (just like before). So, 76 out of 78 found relief from insomnia using QiGong without the need for drugs.