Bought a kit from Ray Jardine for the Backpacker Quilt, used basic DIY Gear Supply instructions to make the underquilt. Slept out in the yard last night, kept me toasty to 37 degrees. I suspect much lower temps are reasonable, especially if I start layering myself up (just pj's last night).
Bought the camo fabric half price at a local fabric store. Both were fun projects, this was my first time sewing. My wife (a quilter) helped me out a lot.