If you've got a ton of plastic shopping bags laying around and the inclination to roll up your sleeves you can turn them into a DIY carrying case for your laptop.
The wikiHow guide walks through creating the sleeve—the general principle is that you use an iron to fuse the plastic bags after folding them over repeatedly—making them strong enough to carry the weight—and then sewing them all together into a sleeve. You'll need a sewing machine, an old sweatshirt or other soft fabric for the inside, and some strips of velcro to keep the sleeve shut once the laptop is placed inside—a great use for those extra grocery bags you have laying around.
For more DIY grocery bag goodness, check out how to fuse plastic grocery bags for crafting. Thanks, Trish!