I really want to ask what the hell a good morning is. But last time I did, you guys were all "uhhuhuhuhuhuh."
Mostly lower back exercise, some hamstring involved.
You're standing with a barbell on your back as if you were about to do squats. You keep your legs straight (straight but not like locked in at the knees), then you slowly bend forwards at the waist, keeping your lower back straight and your head looking upwards. Basically going to parralel, and then back up. If that doesn't make sense, google will help you.