I agree, and thankfully we're dealing with mostly regional visitors to small local business/organization websites. Not a global audience. That being said, it's hard to think of a simple question, with little to no ambiguity.
Once example is for a landscaper: What is the color of healthy grass?
The answer is "green" of course, but grass is common in our region. That question would not work in a culture or region unfamiliar with "lawn grass".
Yes, I would go for simpler stuff (word or digit puzzles) and package it in a way that is friendly for screen readers. So... No images or video, or at least one alternative to them that at the same time does not make it easy for the bots...
This has the added benefit that translators will be forced to come up with a translation that makes sense when your projects gets to a point that it needs i18n.
Once example is for a landscaper: What is the color of healthy grass?
The answer is "green" of course, but grass is common in our region. That question would not work in a culture or region unfamiliar with "lawn grass".