My gran thought that liquid paraffin applied to my skin as achild would stop me from burning (in the tropics). God knows why she thought that. I stank! And was wary of lit cigarettes. Needless to say it didn't work and I fried.
She bought a 6 foot long chest freezer from a shop which was going bust, and put it in the hallway. Our house looked like Iceland (Kerry Katona, not volcano) when you walked in. She bought half a cow from a local farmer to put in the deep freeze. We could have had fillet steak, but no, she kept that for best (?) and we ate the offal. Never did eat that fillet steak, it was probably still in the freezer when she died.
Would refuse to pay the council to remove old ovens or whatever, so would wait until the dead of night, we would dress up like burglars and would fly tip the oven (by hoiking it over a 6 foot wall into allotments, or shioving it down a rough path and pushing it into the sea over the harbour wall). Ilfracombe residents of the 80s - that oven on the beach in August was mine.
Same happened with hanging baskets - she would refuse to buy Busy Lizzies or lobelias or whatever to make her hanging baskets, so we would sneak into municipal parks at dead of night and nick 'em.
What eccentric or frankly insane things did your parents or guardians do?