Can you see out of a glass eye?
Convinced my other half that wombles are real. Grey, about the size of a badger. Obviously don't dress up like they do on the telly, origanate from Eastern Europe, hence Uncle Bulgaria.
She also beleived that it is easier to a ride a bike south than north. The earth in;t a perfect sphere, about 80miles shorter round the poles than the equater, so you get further from the centre as you go south (or north if you are in the southern hemispere) Had a good laugh at her when I told her it was rubbish. Was reading a geology textbook some weeks later and said 'you know what I said about it being easier to go south on a bike? Turns out it's actually true!.' Got her with the same thing twice.