Mum bought herself a lump of steel from some fancy german shop. It now sits in its own customised "soap dish" in her bathroom.
Claiming to possess amazing odour-removal properties, this lump of steel must be used under running water for it to work. Dad also believes in it and claims that it really removes smells from his hands.
Anyway, since none of us can fathom the scientific logic behind its mystical powers (how Mum and Dad are scientists is beyond me at this point), my brother and I have decided that it makes for amusing arguments.
"I saw it at Daiso going for $2 -- you got cheated."
"Why don't you just rub your hands on the kitchen sink?"
"Just put a spoon in every bathroom."
My favourite: "Mum, as long as you're using that lump of steel soap, you have no credibility!"