The need for CD cases is dwindling, but for that same reason it's less likely you have an old jewel case laying around when you need one. Geeky blog Nerd Paradise devised a simple way to make CD case out of a sheet of paper for those rare instances when you need one.
It's a remarkably simple five-step process that works great in a pinch when you have to hand someone a physical disc. The sleeve itself is surprisingly sturdy and even includes a little tuck so it doesn't fall apart. No tape, staples or clunky jewel cases are required, so you can store a full stack of these in a small place if need be. Hit up the post on Nerd Paradise for a close look at all the steps.
How to build a CD Case out of a single sheet of paper [Nerd Paradise via Reddit]