Bucket bathwater / washingup-water to flush the toilet.
Don't run a freezer.
Walk to school in the pouring rain, even though we have a big metal waterproof car.
Unscrew for recycling tiny metal screws from broken plastic toys (almost always gifts from outside our nuclear family, honest!).
Reuse wrapping paper.
Used to rely on guinea pigs to mow the lawn.
Try to mostly feed pets on leftovers.
Won't let any of us buy new clothes unless existing wardrobe item has (truly, utterly) worn out.
Use cut up rags instead of disposable tissue (I do toss the rags when they're grotty.. .my definition of grotty is probably beyond most people's, mind).
Buy organic cotton sheets, and *cotton/hemp clothes.
Probably a LOT of other weird things I don't even think about or would never admit to in public.