I decided to take a leaf from NYC Resistor and create an edible QR code. The one thing I don't like about theirs is that, while edible, it certainly wouldn't taste the best. I wanted to make one that would actually taste good.
6 hours of work later, I had finished my task. I made it out of graham crackers, chocolate chips, and marshmallows, with a thin layer of frosting on each graham cracker. The only problem was, I just didn't have the heart to eat it after putting that much effort into it. My dad suggested gluing it to a piece of cardboard and taking it to work to hang up at my desk, which is what I'm planning on doing at present.
The code is actually scannable (and results in a URL that redirects to this blog post). I'll post pictures soon.
My next idea: QR fruit snacks. A single snack would be in a package, and it'd have some message (a joke, perhaps) encoded on it. Expect to see this on the market in ten years.