Not a bag to put on one's foot, well kinda but no. A bag, filled with sand, that hacky sackers like.
Gilbert did some research and found that microfiber fabric was tight enough to hold sand. I actually had some on hand. He also looked for patterns and came across a blog I follow. She's in my blog list, The Purl Bee. The pattern is for a beach ball type ball which Gil and I agreed would work. Here's her pattern and tutorial: http://www.purlbee.com/fabric-beach-balls/
I told Gil I wasn't the greatest sewer but he encouraged me.
He would, he wanted a sand filled footbag!!!
Unfortunately this one is a bit big. No problem, we'll go a bit smaller on the next.