Have you ever heard of a watermelon sandwich? Me neither, until the other day when I met a lady who claimed to be quite fond of them—just bread, watermelon, and a pinch of salt. That's even weirder than my mom's banana-and-mayonnaise sandwiches.
What weird sandwiches have you encountered?*
* Sandwiches seem to be one of those open-ended food formats where culinary idiosyncrasies and embellishments can really flourish.