What is a great rotational stretch to open up my spine?

When stretching your spine, be sure not to rotate to discomfort.  Rotation of the spine is something to be very careful with and something I advice you seek professional help with prior to completing.  A stretch that will assist is the following:

• When in the seated position, cross your legs.  Next be sure to stand completely upright and slowly twist one side of your body towards the other.  For example, twist your left side towards your right.  As you do this, have your left hand lightly graze your right knee and use this as a reference point.  Again, be sure not to over rotate.

The criss cross stretch is an easy stretch for your back, abs and hips. It feels great. I do this a lot while I am sitting on the ground. 

Sit with your legs crossed in front of you. Keeping your torso upright and the top of your head in line with your tailbone take your right hand to your left knee and place your left hand on the ground behind you and slowly twist. Remember that you want to stretch only to where it feels good. Take two deep breaths and switch sides four times. For a more advanced stretch, sit in lotus position (which is legs crossed with ankles on top of your crossed legs).