As far as I understand it, some orthodox jews are not permitted to do any "work" on the sabbath.

Some factions believe that flicking a light switch is "work," or that pressing a button is "work." So some enterprising fellows have been creating ingenious inventions to allow observant orthodox jews to live comfortably while still not technically violating their rules.

It all seems pretty silly to me, but you have to admit, it is indeed hacking and I think the devices are clever.

One specific example is an elevator, which has a sabbath mode. On the sabbath, it will stop and open its doors at every floor, over and over, so that an observant rider can simply walk on, and walk off at their desired floor, without the perceived sin of pressing the button for their floor.