Yoga: Core Cross Train,with Rodney Yee. Gaiam; gaiam.com
"Core" is a popular word that generally means "belly," though of course it carries more weight. Here it refers to the target of the DVD's active and restorative practices that together provide a balanced workout.
Rodney Yee has been making yoga videos for more than a decade, and his experience shines through in these practices. (Full disclosure: I've worked with Yee for 25 years.) The workout is a deceptively challenging sequence of twists, forward bends and backbends, and infamous belly asanas like Navasana (Boat Pose) and Lolasana (Pendant Pose). I guarantee it will have the desired effect on your core—I felt sore belly muscles after only one run-through.