Well, I got really inspired by some fabulous fun funky usable art where geeky nerdy science meets crafty goodness aka "instructables."
Here's a fused plastic zipper bag using plastic candy bags from an instructables contributor.
Or this appliqued fused plastic bag from another instructables fan.
You basically take 8 layers of plastic bags, sandwich them between parchment paper, and melt away after you finesse your talent at gaging heat, pressure, and timing the process.
Etsy has a tutorial on this basic process and moon>sun has more details and hints. (How did I not know there was a mass crafter-craving for this knowledge?)
With a little luck and some skill you can end up with something like this quick and lovely "farmer's market bag" from Modern Cottage....
Or this professional quality lined version from Moon > Sun.
And hey, it counts as sustainable under the "reuse" category right? So maybe I'll accidentally forget the reusable market bag so I can get some of the pink and purple plastic bags that merchants use around Easter...