The original project I found here at AllPeopleQuilt.com, though I did make some modifications of my own such as adding an extra row and column to the quilt making it a square wider and longer. Since my husband is so tall I didn't want his feet hanging off in the grass! Also instead of batting I used a thicker fabric (corduroy) for the backing and left out the batting all together. The finished quilt is already thick enough without some extra batting. And basting I just tied the two layers together at the intersections of the squares.
With the leftover material I made a bag to carry it in as well! And there are still jeans left!
One comment on cutting your jeans: I included lots of seams and pockets since I didn't want to waste any extra material and yet it is still so comfy to sit on! The pockets and designs will be fun for little kids to explore as well!