Getting answers wrong isn't the only way to look an idiot. It's striking how effective asking the wrong questions can be.
"Is it invariably wrong to act selfish?"
"Is consequentialism or deontology right?"
"How certain does induction make us?"
"What's a certain statement?" (as in come up with one)
"What would make a good foundation for our knowledge?"
"What's more important, my joy, or starving children in Africa getting a meal?"
"Is love or happiness more important?"
"What if I have to go to the doctor, but my child doesn't want to wear his seatbelt, and I'm in a big hurry, then can I beat him?"
"Did you know that two thousand rain forest species go extinct every year?"
"Did you know that if we don't anchor Australia, a sea snail might be crushed?"
OK, some of these are kinda cheating, but some are incoherent philosophical garbage that a lot of otherwise reasonable people waste time thinking about.
(I don't think these examples are very good. As I don't spend my time on this kinda question, I'm not all that familiar with many of 'em. I tend to stop reading in disgust when I encounter them, and then forget about it.)