There's a British panel show I'm addicted to (QI), and one of the frequent guests in its earlier seasons was American comedian Rich Hall. I always thought that he looked strikingly similar to Moe Szyslak but just chalked it up to coincidence.
After years of wondering, I finally bothered to look up who Moe was actually based on. Lo and behold, it's Rich Hall.
So, I guess it's less "today I learned" and more "today I confirmed my random theory".
Yeah, I'll admit he definitely looks less Moe-like back then. I was going by the Wikipedia page and the source it lists. Groening has confirmed it, FWIW, so I guess they could have designed Moe as an older Hall?
Dunno if that's a reach on my part, lol, but I've got this video versus word-of-god and both are compelling.