I find YouTube tai chi videos by Don Fiore to be wonderfully easy and helpful. He doesn't teach complex tai chi forms, but rather breaks movements down so they're easy to learn and practice. His "Tai Chi for Seniors" program is great for starters. Also, he incorporates Qui Gung movements, which are even simpler than those of tai chi. None of this is strenuous exercise, and it is a lovely way to get going.