My college roommate, Kris, and her daughter suffer from migraines, so when she asked me about making some rice bags (to freeze rather than microwave), I was happy to oblige.
I modified this pattern from one that was on Sew Mama Sew because she wanted them to be 12.5" x 6". I kept it simple - no piecing. I also added an inner muslin bag with a velcro closure - only because we don't live remotely near each other - so I have to mail them and she has to fill them. I wanted to make it easier for her! What's nice is that they are totally washable.
And, yes, her daughter is a Spartan. We did not go to Michigan State...Fire Up Chips!