Most fun I've ever had submitting a talk proposal
For this isn't the final format that was actually submitted, but it was a high point of the brainstorming that Sebastian and I did for a couple talk proposals over the weekend (we ended up with 1 workshop, 1 joint talk, and 1 solo talk submissions).
They're meant to be satirical, by the way. I don't think people actually interpret messages in this extreme a manner.