What are some contests that you'd want to join but not host?

I'm curious to know what kind of contests people want but don't exist.
For me, I'd join a writing contest where romance is not allowed to be the main theme of a story.
I'd also join a contest where people have to explain why they love their favorite idol with one sentence.
If anyone sees anything that they wouldn't mind hosting, feel free to 'steal' an idea or two.
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