Tell a play-of-words joke in a language other than English. Explain it between spoiler tags (like this). See how many of the language's learners get the joke...
Here's one in [flag]de[/flag] German:
Gibt es einen Unterschied zwischen Theorie und Praxis?
Ja, in der Tat.
Translation: "Is there a difference between theory and practice? Yes, indeed.
Literal translation: "Is there a difference between theory and practice? Yes, [it's] in the action.
I was looking for [flag]lb[/flag] Luxembourgish puns, but all I could find was this Facebook group with stupid jokes like the following:
Ech caneloni mei bei den Italiener iesse goën.
Ech kann elo ni mei bei den Italiener iesse goën. = I can never go dine at the Italian place again.
"kann elo ni" ("can there never") is pronounced almost like "caneloni," a type of Italian pasta.