We may reuse the plastic bags we pick up from various stores, but they often end up in a landfill anyway, because they get used for picking up dog poo or collecting garbage. If you really want to reuse old plastic bags, you can wave a floor rug that's actually pretty cool.
The folks over at Homestead Weaver put together this DIY project with plastic bags and a loom, but their instructions note that you can still make the rug by knitting or crocheting if you don't have weaving equipment (which is likely the case).
The result is actually pretty cool, and it's a great way to use those bags that would otherwise turn into garbage. However, if you don't need a rug you can also make a placemat, tote bag, or even a pair of sandals. Thanks for the tip, Matt!
Plastic Bag Rugs [Homestead Weaver]