Oh wow, what a question! How about someone saying KFC chicken is actually good!
What is the dumbest thing you've ever seen/heard someone do/say?
It,s always funny when people blow on something like dust and it just gets in their eyes instead.
The BBC Athletics Commentator Ron Pickering (no longer with us alas) famously said "She's completely lost her sense of spatial awareness" when he meant "She's fallen on her a**". We once had another commentator, David Coleman (also recently deceased) who turned that sort of nonsense into an art form. Private Eye, a satirical magazine, published a book called Colemanba**s to record his more absurd utterances. How about these:
“Forest have now lost six matches without winning.”
“If that had gone in, it would have been a goal."
“That’s the fastest time ever run – but it’s not as fast as the world record.”
You'll find a "Spitting Image" impression of him in this at about 06:50